Light effect editing - Limit shininess range

It used to be [0..100] now it's [0..1] to match an upcoming change to the underlying
effect implementation.
Merge remote-tracking branch 'upstream/develop' into develop
Light node hiding / showing

- Add "Show Lights" menu item to the "Document -> Show" menu. This toggles the
hidden state of all light icons in the stage.
- Toggle hidden states of individual lights via the visibility column in the sequencer.
- Link the state of the "Show Lights" menu item to the hidden state of all lights. If all
lights are hidden, the menu item is off (checkmark hidden). Otherwise the menu item
is on (checkmark visible).
- Add willChangeValueForKey / didChangeValueForKey for showLights and showJoints
at the end of -[AppDelegate replaceDocumentData:]. This makes sure the corresponding
menu items are synchronized with state of the document after loading.
- Move the "Show Joints" menu item into the "Document -> Show" menu.
Light editing - Add a default light to the scene

If there are no lights in the scene already, use a default light that is centered in the stage.
This light is not saved with the scene, it's only a convenience for editing. If there are lights
in the scene but they're all disabled then the default light will not be used.
Retina support WIP
Retina WIP
Merge remote-tracking branch 'apportable/develop' into retina

Conflicts:
	SpriteBuilder/SpriteBuilder.xcodeproj/project.pbxproj
Retina support for CocosView
Determine backing scale dynamically
Update cocos2d-swift to retina branch
Stage light editing

Add a "Stage Light" sub-menu to the "Document" menu that allows the user to adjust the
stage light when it is enabled. It is still disabled automatically if the user adds lights to the
current scene.
Update to latest cocos2d
Merge remote-tracking branch 'apportable/develop' into retina
Initial commit of color channel offset effect files
Merge pull request #1206 from stuartcarnie/retina

Retina support
updating Cocos2D submodule to release-3.4.1-beta.1
SB integration for CCEffectColorChannelOffset
include CCColor in Swift bridging header
Merge pull request #1221 from KoboldKit/develop-steffen

include CCColor in Swift bridging header
Add preview of system fonts in menus