song.cpp:
translated an italian comment
hydrogen.h
hydrogen.cpp

Added a method
	sequencer_setNextPatternCategory
that works similar to
	sequencer_setNextPattern

in additions to "int pos" it takes an argument "QString category" and

- toggles the pattern on position "pos" in the list of patterns with the
corresponding category
- turns all other Patterns with the corresponding category off

in order to turn the patterns off at the beginning of the next bar, a
"m_pNextPatternsOff"-queue was implemented analogously to the
"m_pNextPatterns"-queue.

Sidenote:
I did not understand the parameters "bool appendPattern, bool
deletePattern" in sequencer_setNextPattern