Small fixes in setup

- Freeze DjDT version for now since 1.0 isn't compatible with Dj 1.3
- Add the cache/ directory to .gitignore
Harmonize reported Django version with the one installed by requirements.txt
Remove DJANGO_VERSION from the recommended settings

- It adds a headache (it needs to be maintained)
- It can already be obtained by djang.get_version()
- forum_modules/updates/base.py already uses the above method to report the correct version
Merge branch 'remove_dj_version'
Merge branch 'add_requirements_file'

Conflicts:
	requirements.txt
	settings_local.py.dist