Makefile: Added 'make cleaner' and fixed some hard-coded paths.
The 'cleaner' target removes the whole build folder,
the 'clean' target does not always remove all build files
e.g. if building with code coverage arguments.

README-md: Removed 'php5-cli' from the dependency list.
Read fullscreen mode from the config file.
Added fullscreen option to the settings dialog.
Fixed Android build for the fullscreen option.