Remove bit-field.
Remove RiteFile as no used.
Reduce temporary memory allocations. They are redundant.
Modify the type of line-number to uint16_t. Type short is not portable. And it cannot be more than UINT16_MAX because of the mrbc binary format.
Reduce temporary memory allocations. They are redundant.
Remove str_to_mrb_int(). There is some reasons.
 It is not used in the core.
 It does not have mrb_ prefix.
 strtol() is slightly heavy and we have similar API.
Add CHAR_BIT check. There are uint8_t to char conversions.
Display the command line when mrbc is kicked in the verbose mode.
Merge pull request #1104 from monaka/pr-simplify-dump-load

Simplify dump/load
Merge pull request #1105 from monaka/pr-display-more-information-in-verbose-mode

Display the command line when mrbc is kicked in the verbose mode.
Remove API mrb_string_value(). There have mrb_str_to_str() in the core. And mrb_string_value() is no merit to keep using.
Merge pull request #1106 from monaka/pr-remove-mrb_string_value

Remove API mrb_string_value().
Fixed testrb load path
Merge pull request #1107 from masuidrive/fixed_testrb_path

Fixed testrb load path
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.
Change to return the exception object when an exception occurred in mrb_funcall
Add null char terminate to each symbol name.