make test/assert.rb cruby compatible
add test/bintest.rb
add conf.enable_bintest and run_bintest
add regression for #1564
add regression for #1572
add regression for #1563
enable bintest for travis CI
add a comment for enable_bintest in build_config.rb
Increase test coverage of mruby-struct
Merge pull request #1659 from carsonmcdonald/threestructtests

Increase test coverage of mruby-struct
describe call stack overwritten problem of mrb_get_backtrace; close #1661
escape non-ascii characters correctly in String#inspect
Merge pull request #1662 from h2so5/fix-string-inspect

escape non-ascii characters correctly in String#inspect
fix utf-8 codepage
Merge pull request #1663 from h2so5/fix-utf8-codepage

fix utf8 codepage
add enable_debug to build_config.rb
add callback invocation from OP_DEBUG
clone Class/Module rightly
Merge pull request #1664 from h2so5/clone-class-module

clone Class/Module rightly
move range aware aget to array.c from mruby-array-ext gem