Add support for Android 2.3+

There have been plenty of ppl involved in creating this version.
I don't wanna mention names as I'm sure I'd forget someone so I
just tell where help has been done:
- The partial android versions done by various ppl
- Testing on different android devices
- reviewing code (especially the in core changes)
- testing controls
- reviewing texts

A big thank you to everyone helping this to be completed!

1 files changed, 130 insertions, 0 deletions

diff --git a/doc/README.android b/doc/README.android
new file mode 100644
index 000000000..d515b48d5
--- /dev/null
+++ b/doc/README.android
@@ -0,0 +1,130 @@
+Minetest Android port
+=====================
+Date: 2014 06 28
+
+Controls
+--------
+The Android port doesn't support everything you can do on PC due to the
+limited capabilities of common devices. What can be done is described
+below:
+
+While you're playing the game normally (that is, no menu or inventory is
+shown), the following controls are available:
+* Look around: touch screen and slide finger
+* double tap: place a node or use selected item
+* long tap: dig node
+* touch shown buttons: press button
+* Buttons:
+** left upper corner: chat
+** right lower corner: jump
+** right lower corner: crouch
+** left lower corner: walk/step...
+   left up right
+       down
+** left lower corner: display inventory
+
+When a menu or inventory is displayed:
+* double tap outside menu area: close menu
+* tap on an item stack: select that stack
+* tap on an empty slot: if you selected a stack already, that stack is placed here
+* drag and drop: touch stack and hold finger down, move the stack to another
+  slot, tap another finger while keeping first finger on screen
+  --> places a single item from dragged stack into current (first touched) slot
+
+Special settings
+----------------
+There are some settings esspecially usefull for Android users. Minetest's config
+file can usually be found at /mnt/sdcard/Minetest.
+
+* gui_scaling: this is a user-specified scaling factor for the GUI- In case
+               main menu is to big or small on your device, try changing this
+               value.
+* inventory_image_hack: if your inventory items are messed up, try setting
+               this to true
+
+Known issues
+------------
+Not all issues are fixed by now:
+
+* Unable to exit from volume menu -- don't use the volume menu, use Android's
+  volume controls instead.
+* 512 MB RAM seems to be inadequate -- this depends on the server you join.
+  Try to play on more lightweight servers.
+
+Versioning
+----------
+Android version numbers are 4 digits instead of Minetest's 3 digits.  The last
+number of Android's version represents the Android internal version code. This
+version code is strictly incremental. It's incremented for each official
+Minetest Android build.
+
+E.g. pre-release Minetest Android builds have been 0.4.9.3, while the first
+official version most likely will be 0.4.10.4
+
+Requirements
+------------
+
+In order to build, your PC has to be set up to build Minetest in the usual
+manner (see the regular Minetest documentation for how to get this done).
+In addition to what is required for Minetest in general, you will need the
+following software packages. The version number in parenthesis denotes the
+version that was tested at the time this README was drafted; newer/older
+versions may or may not work.
+
+* android SDK (x86_64 20131030)
+* android NDK (r9d)
+* wget (1.13.4)
+
+Additionally, you'll need to have an Internet connection available on the
+build system, as the Android build will download some source packages.
+
+Build
+-----
+
+Debug build:
+* Enter "build/android" subdirectory
+* Execute "make"
+* Answer the questions about where SDK and NDK are located on your filesystem
+* Wait for build to finish
+
+After the build is finished, the resulting apk can be fond in
+build/android/bin/. It will be called Minetest-debug.apk
+
+Release build:
+
+* In order to make a release build you'll have to have a keystore setup to sign
+  the resulting apk package. How this is done is not part of this README. There
+  are different tutorials on the web explaining how to do it
+  - choose one yourself.
+
+* Once your keystore is setup, enter build/android subdirectory and create a new
+  file "ant.properties" there. Add following lines to that file:
+  
+  > key.store=<path to your keystore>
+  > key.alias=Minetest
+
+* Execute "make release"
+* Enter your keystore as well as your Mintest key password once asked. Be
+  carefull it's shown on console in clear text!
+* The result can be found at "bin/Minetest-release.apk"
+
+Other things that may be nice to know
+------------
+* The environment for Android development tools is saved within Android build
+  build folder. If you want direct access to it do:
+  
+  > make envpaths
+  > . and_env
+  
+  After you've done this you'll have your path and path variables set correct
+  to use adb and all other Android development tools
+
+* You can build a single dependency by calling make and the dependency's name,
+  e.g.:
+
+  > make irrlicht
+
+* You can completely cleanup a dependency by calling make and the "clean" target,
+  e.g.:
+
+  > make clean_irrlicht