Change any echo command with args to printf, and remove some unneeded ProGuard options
Remove obsolete Android SDK conditionals in EmuFramework and fix Screen method typo
Refactor base Android code and combine with input code
GLSL Shader Updates

* Add Scale2x shader to EmuFramework
* Load shader sources from shaders subdirectory in app resources
* Update uniform handling
Split out some Linux code from the X11 module into a separate module
1.5.20-beta2

* Add AArch64 defines for Snes9x EX+ and C64.emu
* Fix array index overflow in MD.emu SRAM init code
* Fix array index overflow in MSX.emu FM OPL init code
* Add clean makefile targets
* Remove some obsolete makefiles and make minor source cleanups