Qualify mrb_yield_*'s argv `const`.

Refactoring for kh_put

add assert before write khash del flags

Fix invalid hash type

Add MRB_TT_HAS_BASIC_P macro.

Make bintest enabling like other `enable_xxx` methods.

Fix wrong `mrb_bug` use found with mruby-clang-plugin.

Fix build_config.rb for ArduinoDue

Add MRuby::Build#disable_cxx_exception to force C++ ABI disable.

Fix C++ files detection for automatic C++ ABI enabling.

Hash#replace should copy default from original even when the default value of the original is not set

Use kh_end instead to n_buckets

Delete khash_mask macro

And fix expression to more simple and readable.

Add args in Enumerator#inspect