Remove support for the older "natural English" script syntax.

Remove support for the older "natural English" script syntax.

The older syntax for scripts tried to express time spans using natural
English phrases, but were more difficult to write and were nonsensical
when put together with other valid expressions that use the modern syntax.

Remove support for the old syntax to simplify the compiler and the script
engine.

git-svn-id: svn://svn.curseforge.net/wow/ovale/mainline/trunk@1043 d5049fe3-3747-40f7-a4b5-f36d6801af5f