Remove bit-fields. They doesn't reduce memory on major environments.
obsolete mrb_object; opposite of bc870ce
rename mrb_basic to mrb_basic_ptr; close #1011
removed compatibility macros mrb_ary_new_elts() and mrb_ary_new4()
Merge pull request #1010 from monaka/pr-remove-meaningless-bitfields-in-irep

Remove bit-fields. They doesn't reduce memory on major environments.