Integrating django-frontend-compiler and replacing the flatui base template with the latest prototype used in other projects.
Removing the PySCSS precompiler definition from settings.
Added the clean_css filter, which enables us to compress css assets on production.
Updating the bower dependencies.
Rejigging the JS context init to update or define, rather than just define.
Remove redundant `base.html` from startproject command.
Merge branch 'master' of github.com:markfinger/ixc-project-template into markfinger-master
Fix up requirements for the template itself and default requirements for projects created with the template.

* Django 1.4+ is required by the template itself.
* Django is not required by projects created with the template.
* Lowercase all package names for consistency.
Remove `main_nav` context processor and sample content. We already have `site_sections`, which should also probably be removed.
Update base template to extend `ixc_core/boilerplate.html`, with minimal sample content and stub blocks.
Code style: PEP8
Sort requirements.
Remove duplicate from `INSTALLED_APPS` setting.
Add docstring and TODO about moving a generic version of `django_environment` context processor into `ixc-core`.