Merge pull request #162 from houqp/houqp-master

update(libk2pdfopt): fix android build
Do not build lua-gettext, do not build input module for Emu (is FFI now)
remove lua_gettext
do not load lua_gettext module
remove FFI to gettext
remove FFI C declaration for gettext
remove test specs and data for lua_gettext
Merge pull request #164 from hwhw/fixes

Remove lua_gettext
fix Android build
makefile refactoring for Android
makefile refactoring
Merge pull request #163 from chrox/master

makefile refactoring for Android
add a function to determine if we're running on Android
add a framebuffer module for Android
start input abstraction for Android
standalone toolchain should be platform android-9, small fix

The standalone toolchain for Android builds should be for platform
android-9, since we will build LuaJIT for that, too.

Also, don't build the Lua/C module "koreader-input" for Android
builds.
Merge pull request #165 from hwhw/android

Android
android fix, now we can run into input.waitForEvent
event handling and the screen blitbuffering still need to take care.
Merge pull request #166 from chrox/master

android fix, now we can run into input.waitForEvent
allow input module trigger framebuffer refreshes for Android