Bug 1030972 - Import tasks from Bugzilla

This is a post-merge cleanup of some of the code (pep8 stuff) and also addresses two issues:

1. The label for "Import task" has been changed to "Import tasks"
2. On the task detail page, if a Bug id exists in the task name it becomes linkified

Note that I am not sure of my solution to #2. I'm not sure if I should have put the code into the view, and also not sure of my use of `|safe` in the template, so I'd appreciate feedback on those.

Thanks @glogiotatidis, that's prefect! The regex you suggested ended up matching other numbers in the name as well, so, for example, a name of "Bob's Task 1 for Bug 12345" contained two links, one for the "1" and one for "Bug 12345". I changed the regex to `r'([Bb]ug (\d+))'` and that seemed to fix the problem. I admit to being a regex noob, so if that regex that I came up with is still sub-optimal please let me know. I have changed the code to use a filer though, and that's working very well.