Added mruby_patch_core gem to get some missing features

Object#method
Array#sort_by!
Hash comparable methods etc...

Author: IceDragon200

mrb_config.rb

@@ -19,6 +19,7 @@
 
   conf.gem core: 'mruby-eval'
   conf.gem core: 'mruby-bin-debugger'
+  conf.gem github: 'IceDragon200/mruby-patch-core'
   conf.gem github: 'iij/mruby-io'                # General IO stuff, File system blah de dah.
   conf.gem github: 'iij/mruby-dir'               # Directory access
   conf.gem github: 'iij/mruby-regexp-pcre'       # Regular expression engine :3