refactor mrb_hash_shift, num_pow, flo_eq, flo_finite_p method
Merge pull request #2531 from kkkkkt/refactor-numeric-hash-method

refactor mrb_hash_shift, num_pow, flo_eq, flo_finite_p method
remove unnecessary mrb_float casting; ref #2531
add write barrier when iv is copied
need to add space for receiver to proc env; fix #2525
Remove some roundoff from mrb_flo_to_str
Merge pull request #2532 from chasonr/float-to-string

Remove some roundoff from mrb_flo_to_str
Refactor flo_mod func in numeric.c
Fix indents in numeric.c
Merge pull request #2534 from suzukaze/refactor-numeric.c

Refactor flo_mod func in numeric.c
Merge pull request #2533 from suzukaze/fix-indents

Fix indents in numeric.c
removed unused variable in range_beg_len
Merge pull request #2535 from kkkkkt/remove-unused-variable

removed unused variable in range_beg_len
refactor class.c methods (fix indent, remove unneed temp value. )
use mrb_false_value instead of mrb_bool_value
Improve replacement math functions for Visual C++.
Merge pull request #2536 from kkkkkt/refactor-classc

Refactor classc
Merge pull request #2537 from chasonr/math-functions

Improve replacement math functions for Visual C++.
refactor mruby method(fix indent. remove temporary value, duplicate procedure)
revert mrb_equal method