Return a list of branches for given repository

		:return: [str]

def branches(self):
		"""Return a list of branches for given repository

		:return: [str]
		"""
		# get all remote branches
		refs = filter(lambda l: isinstance(l, git.RemoteReference), self.repo.references)
		# filter out HEAD branch
		refs = filter(lambda l: l.name != "origin/HEAD", refs)
		# filter out all branches not starting with 'origin/'
		refs = filter(lambda l: l.name.startswith("origin/"), refs)
		for ref in refs:
			self.refs[ref.name[7:]] = ref

		# remove 'origin/' prefix
		return map(lambda l: l.name[7:], refs)