Added Insert, Update, Delete icons to the Explain page
Fixed wrong auto-sizing of single-column result

Steps to reproduce:
1. Open a new Query window
2. Execute any select query.
3. Perform Explain of any query. Switch to "Data output" tab. Column
wasn't auto-sized, and is too narrow.

Column's width was taken from colMaxSizes[col] which is wrong.
Changed to look for user-specified width. If it was not specified,
do auto-sizing.