Added debug infomation section into .mrb file

Add travis_config.rb

Use mrb_check_datatype directly to avoid warning.

use new mrb_format API from mrb_raisef; its only format specifier is "%S" (stringify) and takes mrb_value; close #1062

Add simple usage message for mirb

Fix build error on VS2012 toolchain.

A local variables define beginning of a scope block.
VS2012 unacceptable ";;" in struct definition.

Add test for Random::srand

Remove unused variable

Add test for mruby-random

Support MT instance valiables and activate mruby-random

Use C99 flexible array in pool.c

Refactoring mruby-random

Add kernel#rand, #srand ,Random#rand, #srand method