updates to configuration options
first attempt at handling user-agent strings in more advanced ways

- no longer simply allow/deny "IE".  instead you provide strings and key terms that include entire classes of browsers

- quick docs:

special terms:
"mobile" - denies anything we thing might be a mobile browser
"tablet" - denies anything we think might be a tablet
"touchcapable" - denies anything we think might be touch
"pc" - denies any regular computer (not wise)
"bot" - denies anything that appears to be a bot/spider (not reliable since can be faked)

also any other stuff can match via string matching  For example "MSIE" or "America Online Browser" (see a partial list of user-agent strings here: http://www.useragentstring.com/pages/Browserlist/).  this IS case sensitive currently

the definition goes in new "browser_exclude_rule" config option