use regular macros instead of compatible macros

According to mruby/include/mruby.h,

 /* compatibility macros; will be removed */
 #define ARGS_REQ(n)         MRB_ARGS_REQ(n)
 #define ARGS_OPT(n)         MRB_ARGS_OPT(n)
 #define ARGS_REST()         MRB_ARGS_REST()
 #define ARGS_POST(n)        MRB_ARGS_POST()
 #define ARGS_KEY(n1,n2)     MRB_ARGS_KEY(n1,n2)
 #define ARGS_BLOCK()        MRB_ARGS_BLOCK()
 #define ARGS_ANY()          MRB_ARGS_ANY()
 #define ARGS_NONE()         MRB_ARGS_NONE()
Merge pull request #83 from cubicdaiya/issues/compatible_macro

use regular macros instead of compatible macros
Support current mruby change which was changed symbol API and removed mrb->irep
Add build.sh
Fix increasing arena endlessly and use GC of irep
Support Travis CI for build check only
Update README.md
Update README.md
Activate regexp mrbgem
replace indent space from 4 to 2 (conform to mruby coding standard)
cosmetice change
Support output error line no in nginx error log when raise occured
Change travis notification channel