Changed android api level down to 18

Changed android api level down to 18
Specified OpenGL ES 3 as target feature.
    android/AndroidManifest.xml
    android/initialize_project.sh
    android/jni/Application.mk
Android, forced landscape mode

Android, forced landscape mode
    android/AndroidManifest.xml
Added OpenGL / OpenGL ES context creation

Added OpenGL / OpenGL ES context creation
Also added -Werror to desktop build, to enforce warnings.
    src/SConscript
    src/core/MainManager.cpp
    src/core/MainManager.h
    src/graphics/GraphicsManager.cpp (+)
    src/graphics/GraphicsManager.h   (+)
    src/graphics/ViewConfig.cpp      (+)
    src/graphics/ViewConfig.h        (+)
    src/main.cpp
Added logger column header information.

Added logger column header information.
    src/util/LogManager.cpp
    src/util/LogManager.h