[TxMt] do a lookup at mysql.com documentation of selected text including spaces

[Lang Riley]

Similar to other commands that ship with TM, but escapes spaces for the 
URL.  There is probably a better way to do this, but this works.

Before running command: Do nothing
Command:  open http://dev.mysql.com/doc/mysql/search.php?q=`echo 
$TM_SELECTED_TEXT | tr " " "+"`
Standard Input:  None
Standard Output: Discard

Enjoy and share your improvements please.