added texture caching through raw bitmap caches and memory mapped files

Application: enables caching in ResourceManager if config contains key
"textureCache" with valid path. The directory will be created if it
does not exist
ResourceManager: accepts optional cache directory, attempts to load
bitmaps for texture from cache, creates raw bitmap cache if not found
Bitmap: added support for memory mapping, but kept it to a cross
plattform minimum, only address and size fields and check in deleter.
Unmapping is handled in shared_ptr deleter
BitmapIo: handles writing of raw bitmap files suitable for memory
mapping, loading of memory mapped files and decoration od deleter with
unmap
added temp fir to giconfig for testing
added syslog
added view/layer tree logging
added "composite" field to layer, added accessors to Layer and View, configured it for currently available controls
force return value of currentTimeMicroSeconds to be double in order to prevent wrapping values on rpi
timeval double patch, now for the correct platform
starting to create intended structure: SlideMenuButtons added in place, added cell content creation methods
don't draw hidden layers since compositing cache will not exist
changed event bubble so it starts at lowermost view, even if that deviates from the way flex does it
added debug name
Button background is now used for actual backgrund image, optional icon is displayed in imageView, image and title are hidden if not in use
fixed userInteractionEnabled check that was using the wrong view
removed logging
added bringSubviewToFront
geometry setters now explicitly floor the values in order to prevent nasty animation artifacts that would resize and thereby flicker the cached textures
MenuCell, SlideMenu und SlideMenuButton now communicate the selection state via functors, SlideMenuButton closes itself upon seecton, silenced animation logging, removed GEEvents.h
fixed a bug where textures were not correctly globally tracked and only removed from the list of active textures
Bitmap::draw : added 32bit copy fast path in order to speed up font bitmap packing
optimised buffer usage in quad so hardware buffers are not recreated during every init
all cells now use GEFonts, silenced some texture stats logging, reset display size to height=800 again