Merge pull request #347 from lioncash/master

[Android] Minor XML adjustments.
Merge pull request #348 from lioncash/master

Fix a potential memory leak in menu/rmenu_xui.cpp in function rgui_init().
Add fallbacks to where cgp/glslp's are saved.

If shaders are stored in /usr/shader or similar we need fallback
locations.
Start using C89-style for loop initial declarations for
reusable code module parts that we reuse in other projects. It's
a huge maintenance burden having to change this stuff around everytime
when compiling in non-C99 mode
Convert gfx/scaler to C89-style for loop declarations too
[Android] Update the build instruction file for Android on where to place built cores.