Support local variables information dumping.
Implement Kernel.local_variables for testing dumped local variables information.
Remove `lv_len` and use `nlocals - 1` instead.
Check that `lv`'s length is always `nlocals - 1`.
add Mrbtest::FIXNUM_{MAX,MIN,BIT}
test fixnum overflow for add, sub and mul
Add scr_e, to not reassign to e.
Rename e to exception, scr_e to script_error.
Merge pull request #2235 from yui-knk/add-scr_e

Add scr_e, to not reassign to e.
Fix Hash test
Rebuild no mrb_open mrbgems test when config file is modified.
Merge pull request #2240 from suzukaze/fix-hash-test

Fix Hash test
Merge pull request #2241 from take-cheeze/rebuild_irep

Rebuild no mrb_open mrbgems test when config file is modified.
convert &arg using to_proc; fix #2242
Merge branch 'master' of github.com:mruby/mruby
Fix ISO No.
Merge pull request #2243 from yui-knk/fix-iso

Fix ISO No.
should not use String#<< which is defined in mruby-string-ext; use Array#join instead; ref #2239
Merge branch 'master' of github.com:mruby/mruby
add dependency information based on #2239; fix #2236, close #2239
protect argument array from GC in OP_ENTER