Add args in Enumerator#inspect

Always increment `total` field of `os_count_struct` in callback.

add tests for FalseClass

Pass gem's version information to compilers.

remove tests for unicode chars in regular expression literals.

Check sum of `ObjectSpace.count_objects` values is twice of total objects count.
(Which is CRuby's behavior.)

mruby does not parse escape characters in a regular expression
literal (ref #2007).  It is parsed by the external mrbgem that
provides Regexp class, if any.  These tests should not be in
mruby core but in the mrbgem.

reorder and add tests for 15.2.6.1

Add detection of VC++2010 in build_config.rb

Fix 'make test' fail to build on Windows(MSVC)

Fix ObjectSpace.count_objects document.

Update mruby-head installed on Travis CI

This way other projects can test against it.

Refactor MRuby::Gem::List#check.

* Create mrbgem table before dependencies check.
* Topoligical sort gem list.
* Check circular mrbgem dependency.

add --help option to mruby-config

delete khash member upper_bound

Fix build fail for 'make test' with no mrbgems