Improve graph UI.

- resize graphs on browser resize
- move status field to upper right corner to save some space
- align the legend width to the graph's width
Improve inserting of metrics in graph UI.

- Metric will inserted at cursor position.
- Selected text will get replaced.
- Press <tab> to jump to metrics and <return> to jump back.
Clean up of graph UI's form.

- Removed unnecessary spaces and labels.
- Aligned elements for cleaner look.
Update jQuery to 1.9.1.
Add autocompletion for metrics.
Move css for graphs to graph.css and fix minor/fomatting issues.
Merge pull request #97 from prometheus/feature/graph-ui-improvements

Improve graph UI.