* OpBinaryOp for performance
* Cleanup
* Remove ip limit check in every iteration of the loop.
* Micro optimizations on frequent ops
* Micro optimizations
* Patches
* Removed redundant binaryop operators from compiler
* Merged OpReturn and OpReturnValue
* Cleanup
- add type infos to VM error messages
- add 'Name' to UserFunction objects
- add 'expectErrorString' to VM tests
- replace vm.expectError() with vm.expectErrorString() to make it more explicit
- add source map info to VM error messages
- optimization in function calls
- add file/line/col info to compiler errors
- change stdlib module to be loaded from VM (instead of compiler) so they can be properly loaded after the source is compiled into binary
- VM can take builtin modules optionally
