updated for version 7.4.001
Problem:    Character classes such as [a-z] to not react to 'ignorecase'.
	    Breaks man page highlighting. (Mario Grgic)
Solution:   Add separate items for classes that react to 'ignorecase'.  Clean
	    up logic handling character classes.  Add more tests.
Added tag v7-4-001 for changeset 3e9107b86b68
updated for version 7.4.002
Problem:    Pattern with two alternative look-behind matches does not match.
	    (Amadeus Demarzi)
Solution:   When comparing PIMs also compare their state ID to see if they are
	    different.
Added tag v7-4-002 for changeset e29f11399cce
updated for version 7.4.003
Problem:    Memory access error in Ruby syntax highlighting. (Christopher Chow)
Solution:   Refresh stale pointer. (James McCoy)
Added tag v7-4-003 for changeset 560a6a232950
updated for version 7.4.004
Problem:    When closing a window fails ":bwipe" may hang.
Solution:   Let win_close() return FAIL and break out of the loop.
Added tag v7-4-004 for changeset f6247eaf4e1d