Backfill tests for KVO collections + spies

[Finishes #61156524] tests that KVO collection changes work with spies
rename SimpleCollection to ObjectWithCollection
Move KVO collection spy tests into CDRSpySpec.

Discovered that collection KVO method whitelist was not complete,
added tests to drive out support for spying on KVO observed objects
that contain collections (eg: mutablearray, mutableset, mutable
orderedSet).

Note that dictionaries are not supported by KVO - they
must be wrapped in a custom object that calls the required KVO
boilerplate methods before mutating the dicationary.
Remove focused test
[#61156524] [#149] Add explicit test coverage for properties that are not automatically KVO managed.
[#61156524] [#149] Remove Apple LLVM Compiler 4.0 (and above) array subscript syntax.

- Oops, the subscript call broke on CI due to SDK version, iOS 5.0 env
Fixes up launch image warnings for iOS targets

Introduces an asset catalog
Update modal presentation methods
Fix linker warning in CDRJUnitXMLReporterSpec
Unhide symbols by default in iOSSpecs

This fixes the linker warning about the runtime characteristics of weak symbols
Merge pull request #151 from akitchen/ProjectCleanup

A few fixes to clean up the project
Merge pull request #149 from boundsj/backfill_kvo_tests

Backfill tests for KVO collections + spies
Clean up a few imports and rename two ARC specs
Adds support for checking if a file URL exists

expect(URL).to(exist);
// or
cacheURL should exist;
Adds support for checking if a file path exists (as an NSString *)

expect(path).to(exist);
// or
path should exist;
Create caches directory if it does not exist

This is needed when we run iOS specs outside of the simulator, for
instance in Travis CI or via rake
Refactored test bundle reporter.

Changes:
 - Added Reporters group
 - CDRExampleBase records runTime via startDate and endDate
 - Added new methods for CDRExampleReporter as an alterative to KVO:
   - runWillStartExample:
   - runDidFinishExample:
   - runWillStartExampleGroup:
   - runDidFinishExampleGroup:
   - runWillStartSpec:
   - runDidFinishSpec:
   These methods allow more than just observing when state changes: such
   as timing information
 - CDRReportDispatcher wraps cedar's interaction of reporters to
   optionally support new public interface.
 - Test bundle reporter now reports tests as they start and end.
 - Test bundle reporter no longer uses NSDate's description format.
 - CDRExampleBase's run method is now runWithDispatcher:
Added support for Xcode's focused test runs.
Merge pull request #152 from akitchen/ExistMatcher

Adds a matcher to check if a file URL/path exist
Merge remote-tracking branch 'origin/pr/156'

Conflicts:
	Cedar.xcodeproj/project.pbxproj