New gcylc text view column layout.

* Removes the ```state``` column, puts state icons next to task names, and adds state icons to the state filter checkbuttons.  This is more consistent with the other views, and removes redundant information (the state names are available via hover-over, the legend/key window, and - now - the icon-ized state filter labels).
* Adds ```host``` and ```job ID``` columns.
* Reorders the other columns to put ```latest message``` last.  This is sensible because (a) the message column is wide and expands as longer messages come in; and (b) it is not the most important information displayed, as even critical warnings can be quickly erased by a subsequent info message.
* Fixes the bug mentioned here: https://github.com/cylc/cylc/pull/1099#issuecomment-52719475

![gcylc-text-view-new](https://cloud.githubusercontent.com/assets/2362137/3975857/16278f80-2813-11e4-997d-70b8096594e6.png)


@benfitzpatrick - please review.