Port CLI to click
Add click to deps
Make logging compatible with click's testrunner
Support for default command
Don't depend on vdirsyncer logging code

And avoid random breakage if user has a "wrong" version of vdirsyncer
installed.
Add some tests.

Also remove default subcommand feature because of
https://github.com/mitsuhiko/click/issues/205
-a and -d are now per-command options.
Use temporary db
Rework testsuite
Fix bug

We should rework new though
Add another testcase
make khal new work
Also deal with single args correctly

The -a option for the "new" command was set to multiple=False, which is
why the callback would recieve a single calendar (as single string)
instead of a tuple of calendars.
Remove debug print
Remove global state
Merge pull request #98 from geier/click

Port CLI to click