Fix build
fix: E_LOAD_ERROR use mrb_class_get
Merge pull request #16 from pichurriaj/master

fix: E_LOAD_ERROR use mrb_class_get
Merge branch 'master' of https://github.com/mattn/mruby-require into test

Conflicts:
	mrbgem.rake
Edit in rake script: now only gems that are added into master build_config.rb
script AFTER the mruby-require gem are compiled as separate objects. Those included
before it are compiled into the mruby library.