removed unused variable in range_beg_len

Fix indents in numeric.c

Refactor flo_mod func in numeric.c

Remove some roundoff from mrb_flo_to_str

refactor mrb_hash_shift, num_pow, flo_eq, flo_finite_p method

changed some string method's mrb-aspec

mrb_str_bytesize is a carbon copy of mrb_str_size.  remove it.

mruby core does not support any character encodings but ASCII.

fix build when neither src nor mrblib directory exists.

Fix String#succ. "-".succ should be "."

changed mrb_str_size and mrb_str_bytesize comments.

don't always generate gem functions

timer on windows bug fixed.

Fix a bug that class variable can't be referenced from class method

Class method defined in singleton class should be evaluated in class
context not singleton class context.

fix #2515

fixed evaluation context of eval(string) and instance_eval(string)

removed non-need space