Refs #655: Don't create two invoices on double-click

This uses a Django 1.4 feature and so should not be merged until we've
dropped Django 1.3 support.

Branch: bug/655-double-click-invoices
refs #644 - Add group by year to hourly report
refs #657 - Organize "By Project" on hourly report by project type
OrderedDict isn't compatible in Python 2.6
Moved reports to separate app
Should only require adding 'timepiece.reports' to INSTALLED_APPS.
Migrate reports-specific utilities
Migrate reports templates
Clean up some imports and form names
Merge pull request #672 from caktus/reports-app

refs #671 - Pull out reports into a separate app
More import/form tweaks
@login_required wasn't necessary because having a permission implies being logged in.
Move reports templates back to root templates directory
Moved base template location as well
Merge pull request #670 from caktus/hourly-report

refs #644, #657 - Tweaks to the Hourly Report
Merge branch 'bug/655-double-click-invoices' of github.com:caktus/django-timepiece into bug/655-double-click-invoices
Merge remote-tracking branch 'origin/develop' into bug/655-double-click-invoices

Conflicts:
	timepiece/views.py