Converted 0-100 thumbnailQuality param to appropriate 0-9 value when calling imagepng()

Signed-off-by: Joshua Paling <joshua.paling@gmail.com>
Fix `Undefined index` error. Closes #117
Properly handle database rollbacks when exceptions are thrown
Added error logging for thrown upload exceptions
Fully document polymorphic uploads. Closes #94. Closes #124
Fix App::uses() call for HttpSocket. Closes #101
Thumbnail Helper
Refactory: convert string evaluation in sprintf
Merge branch 'master' of git://github.com/josegonzalez/upload into thumbnail-helper
Merge