Vcspull

- :issue:`43` - fix missing test dependency on anaconda by updating libvcs
- README tweaks

- :issue:`41` Transition uses `libvcs`\_ backend
- :issue:`41` Transition tests from unittest to pytest
- :issue:`40` Major API refactorings and removal of unused code, see the
api reference for more.
- :issue:`38` Improve SVN and git support, thanks `jcfr`!
- :issue:`35` Don't run mercurial tests if `hg(1)` missing, by `jcfr`
- :issue:`36` , :issue:`37` Documentation updates from `jcfr`
- :issue:`34` Fix missing mock library, thanks `jfcr`

[libvcs]: https://github.com/vcs-python/libvcs

- [cli] [internal]: command line arg parsing now uses [click] library.
- [cli] vcspull will use the beginning part of the argument to determine
if its searching by vcs URL, repository name or system path.
- [config] `repo` (the longform for the vcs url) is now `url`.
- [config] [internal] repos are now passed around in a list of
:py:mod:`dict`. :class:`vcspull.config.expand_config` has been
simplified.
- [internal] flake8 and sort imports
- [internal] [dev] Add `Makefile` for `watch_test` (re-running
tests on file change), `watch_flake` (re-running flake8 check
on changes)
- [internal] [dev] Move `.tmuxp.yaml` commands to use Makefile
- [internal] [dev] split up requirements into `requirements/`
folder.
- Drop Python 2.6 support
- [internal] `find_config` renamed to `find_config_files`.
- Rename `get_repos` to `filter_repos`, simplify argument signature.
- [cli] Experimental support for concurrently synchroniznig repos via
:py:mod:`multiprocessing`.
- [api][internal]: Refactor :class:`vcspull.repo.Repo` factory class
into :func:`vcspull.repo.create_repo`.
- [internal]: major internal cleanup of dead code, pep8 style updates.
- [git] [tests]: fix git+https remotes [14], add regression tests.

- [internal]: devendorize colorama

- [internal] [tests]: handle `ERROR` in git cloning, add tests. Fixes
cases like `ERROR: Repository not found`.

- [api] Change the API of :class:`vcspull.repo.base.BaseRepo` and
:class:`vcspull.repo.Repo` to accept arguments as `kwargs`
- [api]: Rename `parent_path` to `cwd`.
- [docs]: Pydoc documentation for `Repo` usage.
- [docs]: Python API example