Set filename in mrbc.c.

ci->nregs for ruby proc.

Publish mrb_hash_delete_key.

Modify irep initialization and GC.

Modify reference to ci.

Initialize mrb->irep array with 0 when realloc is called.

because mrb->ci may be changed in m->body.func.

Modify argument of mrbc_filename.

Improve handling of "exit" and "quit" in mirb. 

function prototypes sorted by call & removed unused (file, io, thread)

khash.h including at line:255

Modify buffer size for filename.

Code formatting in sprintf.c