Converted 26 primitives . Fixed various bugs. New PullableStack.

0. PullableStack: customized to more features
1. Forget: also remove method.
2. Symbol: also build variable reference.
3. Fixed Show Empty Stack Bug.
4.  Added DUP / DROP / SWAP / ROT ( also as PullableStack Command )
5. Added SIGNATURE / DOC  / OVERRIDE / FORGET
6. Added PRINT / FORMAT / EXIT / D / E / S / DEBUG
7. Added IMPORTNS / LOAD / PARSE
8. Interop class no longer use Node as argument.