Added template and install script
Fixed install script
Added template uninstall script
Renamed template install script
Expose nmb_expect to Objective-C

- Move expect DSL functions into Objective-C-bridged DSL class.
- Define macro nmb_expect, which calls new DSL class.
- Bridge Prediction to Objective-C in order to allow
  `nmb_expect(...).to` syntax. This causes matcher extensions to define
  duplicate methods in Objective-C [1]. Mitigate this error by using
  "nmb_"-prefixed names in Objective-C.
- Add defines that remove "nmb_" prefix for beNil, beTrue, and beFalse
  matchers.

[1] https://devforums.apple.com/thread/229668?tstart=0)
Updated template icon. Moved spec to beginning of Xcode template list...it is BDD after all.
Expose nmb_expectBlock to Objective-C
Added colon after 'Spec' in template
README: add Objective-C Nimble syntax
Support before/after suite in Objective-C

Fixing #63 from 32,000 feet over Hanover.
Nimble.xcodeproj: add missing headers

Inexplicably, the project appeared to be building just fine as of
712a3e5029e42911a5988eeee54898edafeb3d27. At some point Xcode must have
reverted to a previous version, and that version was committed.
Rakefile: add test task for OS X targets
Merge branch 'test-script' into endersstocker-template
Rakefile: move templates from shellscripts
Templates: add .icns
Templates: choose Swift or Objective-C
README: add guide to installing templates
CONTRIBUTING: add note on rake task