Changed the name of global_definitions into a more appropriate one,
global_entities, since not functions are added too. + Modified functions
in global_entities.c
Fixed file not file issues of global_entities.h/global_definitions.h
Added test files for the global_entities.c
Bug fixed in pmc_start_peripheral_clock()'s first if-statement.
Added initial comments to pwm.c and pwm.h
Merge remote-tracking branch 'origin/integration' into pwm