Add option to run as non-daemon mode

- Pass on debug option with Django
- Cleanup option parsing
Refactor global code from plinth.py
Update .gitignore
Use Django messages module for showing messages
Remove unused misc utility methods
Refactor global code in configuration module
Merge login_nav template with base template
Remove unused templates err.html and two_col.html
Merge pull request #84 from SunilMohanAdapa/misc2

Add option to run Plinth in non-daemon mode