fix memory leaks in pirc

[plobsing]

Originally reported in parrot TT #16 (http://trac.parrot.org/parrot/ticket/16)

Some places in PIRC use parrot's mem_sys_allocate(); they should be either converted to pir_mem_allocate, for automatic free()ing, or they should be explicitly free()d somewhere using mem_sys_free(). This depends on how easy it is to track where the memory is used, and when it can be free()d. In general, PIRC's pir_mem_allocate should be used.

This needs to be fixed.