`jotmuch launch`, `--build-yaml`, GIT integration, with docs

[fradeve]

Hi David, this PR introduces a bunch of new things I have implemented while switching to Jotmuch as my primary bookmark manager.

• launch will open the last searched bookmark, and accepts a number if the last search returned more than one element
• --build-yaml will save a bookmarks.yaml file every time a bookmark is added, edited or deleted
• the Jotmuch folder can now be stored in GIT, and any change will be automatically committed with a descriptive commit message
• all new functions are consistently documented
• documentation has been reworked and is now a Sphinx project
• a setup.py has been added
• an ArchLinux PKGBUILD has been added
• a Tox file has been added (to build docs and possibly run tests in the future)
• a command to import from Scuttle has been added (jot_import_scuttle)
• no previous functionality has been broken
• code has been refactored to remove some PEP8 errors
• code has been updated to be compatible with the new version of click

If you like this and want to merge it in, I will:

• upload the PKGBUILD to AUR and maintain it
• load the documentation on ReadTheDocs.io so that it is available to everyone

Thanks, Francesco

[davidlazar]

Hi @fradeve,

Thanks for the pull request. Here's some feedback:

• Please split this into multiple pull requests, once for each change you want to merge.
• Fixing the PEP8 errors and updating click would be the easiest changes to merge first (create a separate PR for each of those).
• An Arch PKGBUILD would be great, but I think it should go in the maintainer's repo.
• I'd rather keep the docs as-is (in markdown and on Github).
• Git integration sounds neat, but why not instead write a wrapper script that calls jot bookmark followed by jot dump?