Existing MQ2 macros now usable with ISXEQ

[Lax]

As of today's zip, ISXEQLegacy is included in the MacroQuest distribution, to be compiled with ISXEQ. Similar ISXEQ, this is a MQ2 build and uses the code already written in MQ2, so it requires no extra maintenance.

ISXEQLegacy (which requires ISXEQ) implements the Legacy MQ2 (legacymq2 for the unix name which can be used in standard #! lines at the top of a script, like #!/usr/local/bin/legacymq2) script engine, and adds it to Inner Space. Inner Space will then immediately recognize the .mac extension when used with RunScript and EndScript, and will use the Legacy MQ2 engine to run any macros.

The legacy engine does not currently support addition of commands and objects from plugins, so macros that use /stick or other plugin-defined commands and such will not work until that is added. That's trivial to implement, so we'll see if anyone has interest in this before advancing with that.

Everything else works, to my knowledge.