Created classfor() macro

Created a super-cool `classfor()` macro which turns a class identifier into the `Class` pointer-type for the given class.

The intent here is to avoid the odd-looking `[… class]` and `….class` we all we want is the Class from a given static identifier (not the class for a given instance, which is something that a obj-c call to `class` makes sense for).  Additionally, I'd like to try to improve efficiency and compile-time safety where possible (also to satisfy my own distaste of something like this not being part of the Objective-C language).

Danger: Will exit hard and fast (at runtime) in DEBUG, due to use of getRequiredClass.
Converted existing calls to classfor()

Converted existings calls of the forms `[«class identifier» class]` and `«class identifier».class` to `classfor(«class identifier»)`.
Minor (yet crashing) typo in SceneForCG#circleEdgeColor

Fixed a minor typo in SceneForCG#circleEdgeColor; `sCircleFillColor` was being referenced instead of `sCircleEdgeColor`.  Fixes crash during rendering when switched over to CoreGraphics mode.
Checking in all Pods/*

Decided to check in all files under the Pods directory; although everything should keep working without these, it's a pain to have to run `pod install` every time I change branches with differing (unmerged) pod configurations.

Also:
• Removed Pods-related gitignores.
• Updated README.md's build instructions.
Updated CocoaPods to 0.22.1

Updated CocoaPods (the gem) from 0.20.2 to 0.22.1 (latest) and ran a clean `pod install` (on an emptied Pods dir).
Updated installed pods

Updated the installed pods (`pod update`).  Looks like the net result of this is that FontAwesomeFactory went from version 1.1 to 1.2.
Changed all Pod schemes to shared

Changed all the Pod-related schemes (there appears to be one per pod and a central Pods one now in 0.22.1) to be shared, and thus checked in.  This should fix the Travis build.

Also, a line was added to Pods-resources.sh.  Not sure why it didn't do this before.
P-001 scheme Pod dep added to scheme build target list

In Xcode, changed the P-001.G-imr scheme's Build leftsidethingy (phase? mode? product type?) to build the Pods (Pods.a) target before P-001.G-imr (and thus also before P-001 Tests) in order to get `xctool test` on a clean project to build.

However, leaving the `xctool build -scheme Pods` script step in .travis.yml since just `xctool test` as a single step breaks on Travis-CI.  Yeah, I know: insanity.
Update branch 'feature/puck-dynamics' to latest 'master'

Hand-merged changes in:
	Podfile.lock
Pod updates for feature/puck-dynamics branch

1. Ran `pod install` (after rm-ing `Pods/`); and thus a bunch of changes related to MAZeroingWeakRef due to the 0.22.1 upgrade and including all of Pods/*.
2. Re-shared all Pods-related schemes (including the new Pods-MAZeroingWeakRef) and added the Pods scheme back as the first step of P001's build.