Merge pull request #13 from denniszhuo/master

Major update for AVDECC Controller library and command line application
controller: lib: build corrections
lib: remove AVEDECC_LIB_DIR as a required environment variable
controller: lib: start of linux implementation
lib: controller: got code to build again
Merge pull request #14 from andrew-elder/master

start of linux port
controller:lib: Updated commentation and formatted to correctly display
on Doxygen.
controller:lib: Added implementation for ENTITY_AVAILABLE and
CONTROLLER_AVAILABLE commands.
controller:app: Added command line test functions for ENTITY_AVAILABLE
and CONTROLLER_AVAILABLE commands.
controller: Updated release build path
controller:lib: Added log and notification base class implementations.
Updated source code and cleanup.