Logger: Add new LogCategory interface to allow components to specify their own log categories.
Main: Use log category.
MessageDirector: Use log category.
MessageDirector: Rephrase log messages to be clearer; use appropriate severities.
build: clean cmake file
build: add debug and release specific flags
logger: enable compiler to trim log->debug() and log->spam() as no-op outside of debug mode.
Logging: Updated readme.
Loglevels: Fix CMAKE optimization flags
Loglevels: Fix NullStream declaration.