More debug options, tempo calculation, improved note handling

Added lots of options for playing BMS files, such as skipping
jump events (Goto/Loop), only allowing the main subroutine
to end the track and starting to interpret the BMS file
at a specific offset.

Offloaded tempo calculation into a specific method.

Polyphonic IDs are handled in such a way that notes with the
same ID will be turned off correctly.

May contain remains of me playing around with BMS files
More debug options, improved note handling

Added lots of options for playing BMS files, such as skipping
jump events (Goto/Loop), only allowing the main subroutine
to end the track and starting to interpret the BMS file
at a specific offset.

Polyphonic IDs are handled in such a way that notes with the
same ID will be turned off correctly.

May contain remains of me playing around with BMS files