raise NotImplementedError from Module.constants (15.2.2.3.1); close #1125
method function should return mrb_value
factor out redundant Regexp check into functions
Add syntax error for incomplete instance/class variables
sort mrblib/*.rb files to compile (class.rb comes before error.rb); close #1132; close #1134
Merge pull request #1136 from h2so5/syntax-error-for-incomplete-variable

Add syntax error for incomplete instance/class variables
Add syntax error for incomplete global variables
Improve CRuby rake compatible
Fix exit
Merge pull request #1138 from h2so5/syntax-error-for-incomplete-global-variable

Add syntax error for incomplete global variables
Merge pull request #1139 from masuidrive/build

Improve recent CRuby rake compatibility
Merge pull request #1141 from mattn/fix_exit

Fix exit
use EXIT_SUCCESS and EXIT_FAILURE for exit status; close #1142
parse_args should return either EXIT_SUCCESS or EXIT_FAILURE
comment E_* macros to address concerns in #1143