fix braced arguments + nested macro expansion

[kjs]

PIRC's macro handler does not properly handle braced arguments. Macros can be expanded in a nested manner, only in braced arguments. This needs to be fixed.

[kjs]

I have been looking at the code for the Macro layer in PIRC. It's becoming a maintenance nightmare, even for the author. I would suggest to rip it out of PIRC's parser, and revive compilers/pirc/macro as a preprocessor, just like the heredoc preprocessor. It might be a slight performance hit, but it's worth it.

kjs

[plobsing]

This issue is now being tracked at as issue #2 for  https://github.com/parrot/pirc. ( https://github.com/parrot/pirc/issues/#issue/2)