Refactored CustomFrameBuilder and KiwiFrameBuilder modules as classes

- customFrameBuilder_module (.h/.cpp) has been refactored to a class
CustomFrameBuilder (.h/.cpp)
- kiwirameBuilder_module (.h/.cpp) has been refactored to a class
KiwiFrameBuilder (.h/.cpp)

- These classes no longer need global variables but constructor
parameters (related extern variables have been removed from defs.h)
- application code has been modified
according to this refactoring
Changed variable names and fixed return value in main.cpp

- variable names have been lower-cased
- fixed missing return value in initLogging