Fixes to "hg heads -r FOO": Make it actually work (undefined variable 'rev'; allow to pass a rev parameter). repo.branchlookup() doesn't need a copy of heads because it doesn't modify it. Use None as default argument to heads() instead of nullid. Doc string PEPification.

syntax: glob

*.elc
*.orig
*.rej
*~
*.so
*.pyc
*.swp
*.prof
tests/*.err
build
dist
doc/*.[0-9]
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py

syntax: regexp
^\.pc/