Fix colour validator being case sensitive

Change-Id: I8434b810ba3ee5548467c3fd2b72faed4046a586
Reviewed-on: http://gerrit.dmdirc.com/1572
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Greg Holmes <greg@dmdirc.com>

src/com/dmdirc/util/validators/ColourValidator.java

      * Creates a new colour validator.
      */
     public ColourValidator() {
-        super("^[0-9]|1[0-5]|[A-F0-9]{6}$", "Must be a valid colour");
+        super("^[0-9]|1[0-5]|(?i)[A-F0-9]{6}$", "Must be a valid colour");
     }
 
 }