Added WFD state machine.
Layer out source code

This patch rearranges source code between different folders
wfd        - main folder for wysiwidi component
wfd/parser - wfd parser implementation
wfd/public - public interfaces for wysiwidi component
wfd/common - common code that is shared between wfd layers
wfd/source - source code for wfd source
wfd/sink   - source code for wfd sink
Initial implementation of wfd source based on new state machine
Implement sink state machine
Fix include paths

Move sink and source interfaces to public folder
Use layered include paths to avoid conflicts and
enforce proper layering scheme
Initial sink implementation based on new sink state machine
Implement 'play', 'pause' and 'teardown' commands for source.
Remove unused code in desktop_source

This patch removes obsolete mirac-desktop-source implementation
and renames desktop_source to mirac_broker_source.
Implement play, pause, teardown commands for sink
Remove old sink source files
MessageReceiver refactoring

Refactor MessageReceiver so that inheritants contain less code.
Make shared library interfaces for wisywidi library