Merge pull request #11 from rivera-ernesto/master

Modularize cropping logic
Remove trailing space.
Fix overflow crop rect on set some acpect ratio.
Desable multi touch on crop handle.
Updated podspec.
Fix aspect ratio not being kept on edge cases

In some special cases only on dimension was getting re-adjusted despite setting `keepingCropAspectRatio` to `YES`.
Update README.md
Add CI config.
Add Tests scheme..
Add Tests scheme..
New userHasModifiedCropArea property

Allows to check if there is actually something to crop already.
For instance to show/hide an Apply button or to prompt user to accept/discard an unfinished crop.
Merge pull request #13 from rivera-ernesto/userHasModifiedCropArea

New userHasModifiedCropArea property
Merge branch 'fix_aspect_ratio' of github.com:rivera-ernesto/PEPhotoCropEditor
PECropView: Allow to programmatically set the rotation angle (with or without snapping to 90° angles)

This methods allow to easily implement clockwise/counter clockwise rotations from IBAction methods.
```objective-c
- (IBAction)rotationButtonTapped:(id)sender
{
    [_cropView setRotationAngle:_cropView.rotationAngle + M_PI_2
                           snap:YES];
}
```
Merge remote-tracking branch 'fork/fix_aspect_ratio'
Merge branch 'refs/heads/rotation_methods'