mrb_funcall_with_block: adj. ci & sp after error

see #894 / [ruby-talk:404969]
Add document for array_copy
Ignore *.d, *.o, and /lib
Remove freeze leftovers
Merge pull request #901 from nurse/array_copy-doc

Add document for array_copy
Merge pull request #890 from cremno/mrb_funcall--adjust-ci-and-sp-after-error

mrb_funcall_with_block: raised exception corrupts ci and stack
Merge pull request #902 from brainopia/remove_freeze_leftovers

Remove freeze leftovers
Merge pull request #900 from nurse/ignore-d-o-lib

Ignore *.d, *.o, and /lib