- don't add "..." anonymous field to structs/interfaces if entries are stripped

- don't add "..." anonymous field to structs/interfaces if entries are stripped
- don't print any optional semicolons after declarations inside functions
- indicate non-exported fields/methods in exported types with a comment
  so that the "exported source" is legal Go code
- more tests

R=rsc
DELTA=300  (227 added, 25 deleted, 48 changed)
OCL=34697
CL=34730