Squashed 'floo/common/' changes from f1767ff..e1d33f1

e1d33f1 backport delete workspace and take callback.  Fix bug in getting index (ints can be bigger than 1 digit)
35b9a24 UnboundLocalError
d4c64a8 Always return a bool from utils.can_auth(). Sublime 3 require all WindowCommand.is_enabled() functions return bool.
dfab13c Change msg.error to editor.error_message if we try to connect to a nonexistent workspace.
161964b Fix URL in api.get_workspaces().
d04e321 Add delete workspace command.
e2342e8 Don't die if HTTP response is 204 (no content).
aa71089 Merge pull request #194 from Floobits/kans
d2ce522 Merge python common. Fix conflicts.
fa53e16 Unbreak sharing directories.
5496e27 Don't crash if buf is somehow not populated.
4e2869a made a set_interval.  Unfortunately, when ST reloads, the previous instance keeps on going, but out of reach...

git-subtree-dir: floo/common
git-subtree-split: e1d33f137f725bfc49c5965af3f94f0c9aa9577d
Merge bug fixes from python common.