various makefile fixes

 * verbose `rm`
 * use `jira-python`
 * switch to `python2`/`virtualenv2` due to lack of `python3` support in `jira-python`
 * some fixes for virtualenv
main script and index page
authorization and bookmarkable pre-filled index page
[minor] index: fix labels
Instead of trying to store JSON-unserializable Jira object in `session`, use decorator to provide access to the object.
handle SSL and authentication errors