Fixes warnings that happen on clang. Clang picked up a number of things by default, including:
1. Memset by the size of a pointer rather than by the struct itself 2. inline functions in header files declared only 3. needless casting (although a leaked KWinAdapter is just insane, not sure how to fix that ..) 4. Unnecessary checks for < 0 with unsigned int 5. Member methods hiding virtual functions because they were never overridden correclty 6. Unused isAncestorTo in decor 7. ; after if statement with block proceeding in some places 8. Incrementing a bool