Merge pull request #2 from denniszhuo/master

avdecc_strings and enums
add plantUML diagrams
Merge pull request #3 from andrew-elder/master

add plantUML diagrams
Update all header files. Improve threading. Split out system class.
controller/lib: Moved source files under AVDECC Controller lib directory.
Updated preprocessors and source file namings. Code updates and cleanups.

controller/app: Updated AVDECC Controller command line test application.