Reserved word warning config

This commit removes reserved word warning from the Browse pages and the
warning on structure page can be switched on/off using the config
variable $cfg['ReservedWordWarning']
Added ability to disable MySQL reserved word warning

Disable MySQL reserved word warning $cfg['ReservedWordDisableWarning'],
documentation and ability to change from prefs pane
Merge pull request #216 from ayushchd/reserved_words_issue

Reserved words issue