A new custom software mixer, supports playing streams at any rate, which is needed to emulate the directsound SetFrequency effects (when a ride malfunctions and the music slows down and stops).  The speex resampler is added for this.  Currently samples can be played and their volumes and looping set on an arbitrary number of channels.  Support for FLAC and other streaming formats can be added.
Merge branch 'master' of https://github.com/IntelOrca/OpenRCT2

Conflicts:
	projects/openrct2.vcxproj.filters
cmake build
cmake build
Merge branch 'master' of https://github.com/zsilencer/OpenRCT2
0x006BB9FF, 0x006BC2F3, mixer edit, completed 0x6BB76E
Merge branch 'master' of https://github.com/IntelOrca/OpenRCT2

Conflicts:
	projects/openrct2.vcxproj.filters
	src/window_scenery.c
Added rct_peep struct union (staff_id and guest_peep_varC5)
0x006BBC6B, hook
Merge branch 'master' of https://github.com/IntelOrca/OpenRCT2
hook
gcc fix?
Merge pull request #429 from KingHual/master

Added rct_peep struct union (staff_id and guest_peep_varC5)
Fix #432. Mistake was caused by oppacity bit in colour
Labelled a few peep variables. Added voucher type enum
Switched to no_of_rides instead of staff_type
Merge pull request #454 from duncanspumpkin/fix_432_and_peep

Fix #432 and a few more peep variables named
Fix #455. Since there is no reason to show both quit windows may as well just close the previous one.
Merge pull request #456 from duncanspumpkin/fix_455

Fix #455.
Fixes half drawn doors in scenery window