Merge branch 'dev'
Merge branch 'release/1.1.0'
Add guidelines for branching
Merge branch 'contrib' into dev

Conflicts:
	CONTRIBUTING.rst
Handle as_string in _validated rather than in _format_num
Merge branch 'refactor-number' into dev
Fix as string behavior on py2
Merge branch 'fix-py2-asstring' into dev
Fix `as_string` of Number fields when serializing to default val
Merge branch 'fix-string-default' into dev
Merge pull request #1 from sloria/dev

upstream