added high-shelf and low-shelf filters, positional audio now uses high-shelf filter, significant reformatting/renaming of AudioFilter.h for coding standard
Merge remote-tracking branch 'upstream/master'
add explicit constants inline for documebntation purposes
SQUARE_ROOT_OF_TWO renamed SQUARE_ROOT_OF_TWO_OVER_TWO
Merge pull request #3320 from chansensturm/master

added high-shelf and low-shelf filters, positional audio now uses high-shelf filter