At string_with_format, fix the locale if the format is a Symbol.

If I set Region Format Japanese by Settings app, string_with_format(:iso8601) returns with Japanese style.
Maybe it should be a same value by all locales.

```
Bacon::Error: "2013年-01月-02日 12:15:30.000".==("2013-01-02 12:15:30.000") failed
```
add the timezone option to Time#strign_with_format

i.e.
```
t = Time.now
t.string_with_format('HH:mm:ss', timezone:'UTC'.nstimezone)
```
Merge pull request #133 from katsuyoshi/string_with_format

At string_with_format, fix the locale if the format is a Symbol.
note
added 'cgcolor' method to all classes that have 'uicolor', and moved color specs to one common spec file
renamed file to be more sensible
code consistency
playing with CAAnimation
more CAAnimation fun - fixed keyframe_animation
animations and specs
updates to CAAnimation helpers
version bump for CAAnimation additions
added 'UIView#animate_constraints'
deprecated symbols
official OS X support in SugarCube - FINALLY!
update contributors and version file location
version bump
some NSView helpers
KVO compliance
whitespace