Use `format` function for debugging vm
Add `load` and `load-binary` function
Disable stdout when compile mode
Save/restore arena on compile
Check name for let is not nil
Detect local and free variable index after traversal
Fix free variable index
Change to use traversal compiler
Remove "my-" prefix
Implement inlining function on traversal compiler
Ungetc when shared structure is illegal
Read self referential shared structure #103
Enable producing loop code #97