- changed tab width to 8 chars by default to make test run properly
- excluded 4 files that are not idempotently printed
- fixed a couple of incorrect file position recordings in parser
- fine-tuned layout engine
- white-space formatting reasonable, but not perfect
- no handling of overlong lines
R=r

To use with smaller tabs:           pretty -tabwidth=4 file.go
To use with blanks instead of tabs: pretty -usetabs=0 file.go

OCL=20184
CL=20184