Update the TimeSCons class for use of the sort= keyword instead of

Update the TimeSCons class for use of the sort= keyword instead of
important=.  Fix an old-version Python problem (use of True in
keyword arg initialization).

git-svn-id: http://scons.tigris.org/svn/scons/trunk@4539 fdb21ef1-2011-0410-befe-b5e4ea1792b1