Change scapa and rcapa to size_t, use scapa.
Merge pull request #1601 from carsonmcdonald/srcaptosizet

Change scapa and rcapa to size_t, use scapa.
should not access scope after releasing memory pool
avoid top-level pool release at codegen_error() and fixed some memory leaks
Add is_a? test to cover issue 1477
remove unnecessary keep size adjustment in stack_extend_alloc(); close #1602
Merge pull request #1604 from carsonmcdonald/1477isatest

Add is_a? test to cover issue 1477
Fix ISO no in Array#* and Array#+
Merge pull request #1605 from suzukaze/test-array

Fix ISO no in Array#* and Array#+