some minor changes, bugfixes, started adding new elements

changed skin for drum-computer due to additional features

added to drum-computer:
	pattern length and base (speed)
	variable volumes for all ticks

changed API to provide additional storage facilities
	necessary to export DrumComputer's pattern configuration.

now showing previously selected sample when opening a new one

wave import
	added 8 and 24 bit support (needs testing)

spinner controls rewritten
	they now use a hand-crafted pixel-font
	todo: add letters to pixel font

started adding a new rack element

started adding TTS providers
	maybe there will be a cool speech synthesizer element in future releases