Half-step towards making repo comparison in testlifter.py exportable.

All regressiin tessts pass.
Another step towards making repo conversion exportable.

All regression tests pass.
Some useful CFLAGS for profiling
In the test framework, enable checkouts on bare repositories.
First version of cvscompare.
Check all branches and tags.
Make command line --expand work like CVS

CVS follows the rules:
1) If the file says -kb do that, otherwise
2) If the command line is set follow that, otherwise
3) If the file says anything do that, otherwise
4) Use -kkv

This change means we follow those rules except for the very last one
where we use -ko instead.
Simplify and fully document the handling of tye -k option.

It now requires an argument.

All regression tesrs pass.
Ignore CVRSROOT files by default. The -P option switches this off.

All regression tesrs pass.
Refactor test framework to use more subclassing.  All regression tests pass.
In the test framework, untangle streaming from conversion.

All regression tesrs pass.
One less fixed assumption about names.  All regression tests pass.
Add checkall method and fix symbolic-link handling.
Make test framework clean up after itself.
Don't crap out if proxy directory exists.
Restore compilation without threads.  All regression tests pass.
Banish spurious keyword expansions.
More detail about mismatched file manifests.
Added docs for cvscompare, and a guide to reporting bugs.

All regression tests pass.
More documentation polishing.