Update C++ extensions in build instruction document.

Class.new do not call `class_eval'

Module#initialize set created object for block argument

Change range_check before mrb_obj_alloc.

Use boolean macro in kernel.c

and set self for block argument

for block argument

It is executed per each debug filenames in irep to same ireps(children).

mrb_load_irep_file() caused SEGV

Correct comment in exception test.

Support extension '.cc' in source code listing.

Implement Module#initialize (15.2.2.4.31)

Merge branch 'add-exception-test' of https://github.com/yui-knk/mruby into yui-knk-add-exception-test

Move `Kernel.local_variables` to core.

that not have methods each other

This fix use UINT16_MAX for NULL symbol tag, that means maximum symbol length
is not UINT16_MAX-1.

Add Range#size