compile assert.rb once
use mrb_str_new_lit instead of mrb_str_new for C string literal
Merge pull request #1752 from cubicdaiya/issues/use_mrb_str_new_lit2

Use mrb_str_new_lit instead of mrb_str_new for C string literal
Merge pull request #1753 from take-cheeze/assert_rb

Compile assert.rb once.
add new function mrb_get_backtrace_at() to get backtrace at ci and pc
fix indent
avoid recursion when method_missing happened in inspect; fix #1746
revert 38e9ce21 and API changed; mrb_get_backtrace() -> renamed to mrb_exc_backtrace since this is a backtrace method implementation of Exception; mrb_get_backtrace_at() -> removed; mrb_get_backtrace() -> added to get backtrace in array (like caller)
Delete `!!Notice!!` intro paragraph from README

It's become misleading since the release of 1.0.0 and the launch of mruby.org.
Merge pull request #1754 from pje/patch-1

Delete `!!Notice!!` intro paragraph from README
boot_defclass: super may be NULL
forget to break in the switch statement