Allow shell quoting on CLI

Break up command-line args using shlex rather than string.split

This enables multiple-word tags using quotes:

mailpile> tag/add "three word tag"
mailpile> tag +"three word tag" 20
[Issue #398] Fix the help/variables command and API endpoint
[Issue #398] Add simple test and better displaying for help/variables
Depend on range of spambayes versions, since we don't know distro version.
Merge pull request #492 from chadmiller/master

Depend on range of spambayes versions, since we don't know distro version.
Status update
added alternative package installation for rubygems based on debian version
Merge pull request #495 from maxking/dev

added alternative package installation for rubygems based on debian vers...
add a new api endpoint for importing gpg keys
Moved optional network grapher into plugins repo. Fixes #497
Adding searched=False to search output structure to preserve consistency (viz searched=True)
merge upstream branch
added specific python version
modified import_key to accept string instead of file object
Merge pull request #409 from jwaterfaucett/fix_help_variables

[Issue #398] Fix help variables
Merge pull request #504 from Treggats/add_specific_python_version

added specific python version
Added Jinja extension to assess if a search result item has Label tags in search view, Issue #458
Started adding 'Add to Groups' modal, segmented '.bulk-actions' JS events into separate closures for Issue #463, did some logic for 'Tag' events as per Issue #458
Got basic UI feedback of adding Tags to search items working, Untag is still nor supported yet Issue #458
Updated bulk-actions tooltip for new unique classes instead of .bulk-actions