Some usebility changes

- change desing of header so it is less present in the vision
  - remove box shadows and background color
  - use monospace instead of verdana to look fancier
- make post in list view clickable, so it is easier to
  come from list to show
- the main purpose of this tool is to look at posted snippets
  so we increase the size of the post#show area without
  touching the borders
- make linenumber a fixed with so it doesn't look to big
  on big screens. They will get wider in the moment when
  bigger numbers appear (needs to be tested on IE)
- add Date to post view

Thanks to mpf@ to pointing out this issus
Prevent line numbers from beeing selected
Merge pull request #77 from kmerz/add_info

Usability Improvements