Fix crash on boot

Rename test view controller nib name used to load the example view
controller
Also post a notification when calling the didSelectColor delegate method
DRY, use the base view controller to post fire the didSelectColor delegate message
Update the selected colour image in viewWillAppear so that the checkered image isn't briefly shown when opening the colour picker
Use the height of the gradient view's frame for the gradient tracker crosshair height, allows resizing gradient views
When loading favourites, check the data type before assigning the object to the _favorites OrderedSet, if the type is not what we expected, allocate a new Set
In the HSL Color Picker, set up the views in viewWillAppear to allow gradient views to update correctly if the are moved due to struts and springs layout changes
Add ISColorWheel source for a scalable, mathematically created colour picker
Implement ISColorWheel as the HSL picker
Remove Saturation bar from HSL picker, this is handled by ISColorWheel
Move checkered image to the top right of the screen and add a border with rounded corners
Move Luminosity bar to the bottom of the screen
Move ColorWheel to the top of the screen
Change struts and springs to allow the wheel to resize and anchor the gradients and text in the correct place
Repurposed favourites to save recently picked colours
If a colour is already in the set, move the colour to the front
Set the save to favourites button as hidden
Update gitignore