Added modulate API wrapper.
Added test for modulate.
Added raises, versionadded to doc string.
Allow setting jpeg:sampling-factor option
Merge branch 'master' of git://github.com/mrdanpsmith/wand into 0.3-maintenance
PEP 8  #134
Changelog for #134
Fix incorrect changelogs
Merge branch 'sampling-factor' of git://github.com/ksvladimir/wand into 0.3-maintenance
Changelog for #137