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 ISO No. to Integer#divmod  test.
Merge pull request #2249 from yui-knk/fix-iso

Add ISO No. to Integer#divmod  test.
Merge branch 'dump_lv' of https://github.com/take-cheeze/mruby into take-cheeze-dump_lv
rename lv section header from LOCV to LVAR
resize register number in LVAR section from 32bits to 16bits
Merge branch 'take-cheeze-dump_lv'
Kernel.local_variables to list UPVAR as well
Modify eval for access outer local variable
mv opcode.h -> include/mruby/opcode.h and remove duplication from mruby-eval gem
adjust signedness in mruby-eval gem