Backport enhancements made in Debug panel for Yii 1.1

[samdark]

Debug panel for Yii 1.1 implemented by @zhuravljov is an excellent port of 2.0 panel with some cool additions and changes we can port back.

Toolbar

Here's current 2.0 toolbar:

And here's 1.1 toolbar:

We could remove "Yii Debugger" title and place version number w/o "Yii" there. Will save lots of space for custom panels. done

Index

Current:

1.1:

Status code could be highlighted, dates could be formatted better. done

The stars there are to "pin" a request so it's never cleaned up when debug data limit is reached. These are also in request page:

DB panel

1. Syntax highlighting Implement TextHighlighter yii2#52
2. Ability to run EXPLAIN in place. done
3. Resume (should be called summary) tab shows how many queries of the same type were made, ordering such query groups by execution time descending. Very useful for getting an idea of what could be optimized.
4. Connections tab shows which connections were made.

[samdark]

Splitted the rest into separate issues.