Fixed DataPage assert error.

When a DataPage is displayed, this tries to pass a string to
address.fromVirtual(), causing an AssertionError. Fixed by checking type
of addr. If it is a string, pass to address.fromConventional() instead.
Bugfixes
Make call annotations brief
Fix goto labels

When generating a label, the address was not passed,
resulting in meaningless zero labels.
Minor improvements

- add repr to address
- fix some lint issues