Invoke-release

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- Complete Python 3 compatibility, ensuring end-to-end unicode
- Add ability to sign release tags for increased security
- Relax requirements for versions to permit alphanumeric qualifier suffixes after the patch version
- Relax requirements for version branches, rigidify requirements for version numbers released from version branches
- Support ``CHANGELOG.md`` and ``CHANGELOG.rst`` in addition to ``CHANGELOG.txt``
- Improve wording of some prompts and messages to reduce confusion
- Prepare for open sourcing so that it can be used with our open source projects, like Conformity and PySOA
- Ensure we use colons consistently at the end of all prompts
- Ensure we can roll back partial releases that failed before completing
- Add Travis build and Travis secret for automatically deploying new releases to PyPi

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- Made Python 3 compatible
- Fixed bug in ``rollback_release`` preventing it from working
- Fixed bug in ``setup.py`` preventing it from installing
- Added a ``build_wheel`` task

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- Adding support for storing version in plain text version.txt

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- Add new task for creating patching branches from release tags

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- Make ``invoke release`` work with $EDITOR with params

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- Fixed the install requires that does not work on all machines