Forcing UTF-8 encoding on licenses generation. Fixes #530

Update CHANGELOG for #530

Forcing UTF-8 encoding on licenses generation in Ruby 1.9 only. Fixes #530

Forcing UTF-8 encoding on licenses generation. Fixes #530

The variable is `CP_MASTER_REPO_DIR` and potentially paves the way for
supporting a deeper linting of CocoaPods/Specs. Every check would be
supported, including checking that the files patterns match, except
xcodebuild checks.

Support extracting .tar.bz2 files

Closes #448

This lead to a double execution of setup if the automatic setup triggered.

Update git repo cache if branch isn't found

Chartboost (and likely other sites) distribute source code in bz2
format.  Support for recognizing and extracting these files will come in
handy.

Update AppleDoc install instructions

@tomaz tagged a new version of AppleDoc which resolves the issue requiring
the `--HEAD` param to `brew`, and @adamv [pulled in the change](https://github.com/mxcl/homebrew/pull/14693)
to mxcl/homebrew that both updates to the new code and also uses
the [new compile-time template location](https://github.com/tomaz/appledoc/pull/231)
to avoid the second step.

This caused a Bug that lead to Pods with preferred dependencies to be always
installed.

Closes CocoaPods/Specs#464.

Should fix Travis errors.

closes #490.

This reduces ambiguity and prevents bugs like #489, which was caused by the
Sandbox creating a LocalPods from the spec in the root (if present) and
ignoring the one in Local Pods.

Closes #489.