Added cascade training support

Needs to be documented
Removed unused code
Requested fixes

Tabs to spaces, used OpenCV folder separator function, capitalized
struct name, re-added missing bracket
Indentation fixes

It looks worse than it is. De-indented some code, that’s all…
Removed unnecessary public scope qualifier
Fixed { locations
Addressed comments

Cosmetics, used QProcess instead of system, used File::contains and
File::get, eliminated RectToString()
Replaced execCommand with QProcess::execute()
Fixed bug where arguments not passed to trainer
Added author attribution
Style improvements, fixed static/const/reference
Merge pull request #179 from dgcrouse/master

Added training for cascade classifiers