Added the TLCEval command to the TLC module and provisionally added fix to Bug 279 (TLC bug caused by TLC's not preserving the semantics of CHOOSE).
Added the TLCEval command to the TLC module and provisionally added fix to Bug 279 (TLC bug caused by TLC's not preserving the semantics of CHOOSE).

git-svn-id: 7acc490bd371dbc82047a939b87dc892fdc31f59@26275 76a6fc44-f60b-0410-a9a8-e67b0e8fc65c

lemmy/tlaplus,tlaplus/tlaplus,tlaplus/tlaplus,lemmy/tlaplus,tlaplus/tlaplus,tlaplus/tlaplus,lemmy/tlaplus,lemmy/tlaplus