Confight

* [3c266c8d] Force all loaded files to have the same extension

[ javier.lasheras ]
* [a1646871] OrderedDict for yaml too

* [4a5920af] Adds pypi version badge to README
* [59c47a5e] Drops support for Python 3.3 and Python 3.4
* [dfa9c436] Adds support for Python 3.7
* [6979074d] Fix manpage generation
* [8f6b58f5] Create a parser with ExtendedInterpolation
* [7d74246d] Avoid DeprecationWarnings
* [633b1571] Ordered dicts everywhere

* [736a6493] Adds prefix and user_prefix options
* [023158e5] Adds --prefix and --user-prefix cli options
* [f395fc44] Adapt tests to run in python 3.3 and 3.4
* [a144dab1] Update package metadata

* [a7b46ef1] Adds travis config file
* [5f625da9] Add tox-travis integration
* [1b678173] Adds confight command line tool
* [691e042a] Adds cli unit tests

* [3322a7a4] Allow custom file extensions when format is defined