Starting osx token cache work
Initial implementation of security output parser.

Requires bringing in readable-stream and event-stream modules as
dependencies.
Merge branch 'mac-token-cache' of github.com:christav/azure-sdk-tools-xplat into mac-token-cache

Conflicts:
	lib/util/authentication/osx-keychain-parser.js
	package.json
Successfully parsing output of security(1).

Found some cases in output that original tests weren't catching. Fixed.
Added parser error check to prevent infinite loop.

Added check to make sure we don't try to parse a single line more
than twice - if we get in that state a regex isn't matching and
there's a bug. Rather than hanging, bail out with an error.