Cooler README build status line

Status line is now:
• Very first thing, above the header.
• Trailed by a double-space-seperated, `<sub>`, parenthesized branch name, e.g.: `(master branch)`.
• `<img>` properly vertically aligned with the text.
• All HTML, because of `<img align=…` and `<sub>`, and to make it not look afool.
Minimal README build status img alt

Since Travis-CI can take a few moments (observed up to 10 seconds) to provide the build status image, the alt text often appears for a while (in Firefox at least; WebKit appears to just display nothing prior to image load).  This changes the alt text from a super-long super-descriptive line to an ASCII-arty “[build: …]”.
Merge branch 'feature/models-and-surrogates' into feature/puck-dynamics

Also, preserved existing README.md build status line.
Updated PuckEntity location syntax

• Changed location property's `InchLocation *` type to `id<InchLocation>`.
• Replaced location synthesize with a custom getter that returns a surrogate.
Merge branch 'feature/models-and-surrogates' into feature/puck-dynamics
`pod install`-updated Pods.xcodeproj
Ignoring *.xccheckout files, just for Xcode 5
Switched “persistents” to use `NSIncrementExtraRefCount()`

Now using `NSIncrementExtraRefCount(…)` over `[… retain]` to signify that the prersistents are being retained in a special manner, not intended to be released lightly.  Also switched some `init`s over to autoreleasing named constructors and removed `… release]`s where applicable.
Removing `#import`s from the pch and import finer scopes

Decided in the spirit of getting imports right (and making things leaner overall) to remove the UIKit/Foundation/category additions from the Prefix.pch file and instead get my per-file #imports right (heck, as it was I didn't need any imports in about half my headers).

As a result… a surprising few things broke.  What did boiled down to these:
• Missing UIColor+SDTAdditions, UIViewController+SDTAdditions, and CGAdditions addition header imports
• Missing <CoreGraphics/CGBase.h>, …/CGGeometry.h>, and …/CGImage.h> for CGFloat, GCRect, CGSize, CGPoint, CGImageAlphaInfo, CGBitmapInfo.
• More-specific and missing <UIKit/UIColor.h>, <UIKit/UIView.h>, 

For <Foundation/…>, I've mostly decided to include it all (`<Foundation/Foundation.h>`) since most of the time we need one thing from it, we need a lot.  In a couple of instances, I've only included NSString, but that's not the norm.

Also, for `.m` files I've opted to include a whole framework (`<Foundation/Foundation.h>` or `<UIKit/UIKit.h>`) more liberally since the weight on the build is much less significant and it can become a pain to have to add an import for every new class one uses.

In a few spots, I've eliminated forward declarations for exact imports.  This seems to be the popular (and less headache-inducing) approach for Obj-C.  Well, maybe not the exact part, but that's me.
Update branch 'feature/puck-dynamics' to latest 'master'

Combined intra-line changes in:
	README.md
Update branch 'feature/models-and-surrogates' to latest 'feature/puck-dynamics'

Also updated README.md build status line to reference “feature/models-and-surrogates” instead of “feature/puck-dynamics”.