[kernel][debuglog] Changing Debuglog header format

Changing the '.' to a ':' in the Pid.Tid portion of the header
This way it will not be confused with something that might represent time.
[00003.833] 03449.03865>    will become
[00003.833] 03449:03865>
Also updated the parsing scripts to accept either the old format or the
new.

Test = Ran serial console, piped it through scripts/colorize_logs

Change-Id: I97bd9ca32b7b9bb0b5a60177c4dbdfad3020eea0