Update project comment
Provide version information
Install pkg-config file
Provide default argument for Texture::Lock()
Provide copy operations for AudioDevice::LockHandle
Use SDL2 seek whence flags, not ones from stdio
Add note on installation
Remove demos into more suitable examples

Also add options for conditional build of tests and examples
Add operators to offset a Rect by a Point
Merge branch 'master' into doxygen

Conflicts:
	SDL2pp/AudioDevice.hh