Remove bit-field.
Remove mrb_flt2big() as there is no bignum in the core.
 Add new API mrb_flo_to_fixnum(). You can replace mrb_flt2big() to mrb_flo_to_fixnum() with few modifications.
Change the second argument of mrb_flo_to_str().
 Export mrb_flo_to_str() as API.
Include mrbconf.h as MRB_INT_MAX used here.
Rename mrb_fix2str() to mrb_fixnum_to_str(). This is for naming consistency.
Add null char terminate to each symbol name.
Merge pull request #1115 from monaka/pr-add-null-char-to-each-symbol-name

Add null char terminate to each symbol name.
Merge pull request #1108 from monaka/pr-cleanup-numeric.c-20130329

Cleanup numeric.c
cancel f4c27c6 since mruby.h is required for mrb_value etc. anyway
undef Integer#new; ref #1111
move to_i from fixnum to integer; remove reference of to_int which is not in ISO
Merge pull request #871 from monaka/pr-remove-bit-field-in-mrb_value

Remove the bit-field by mrb_value.tt
revive #to_int
should have rewinded stack on exceptions; close #1113