fixes yahoo/locator#5 don't scan bundle packages
test that parseBundle doesn't yield references to "foo"
test case for symlinked package creating endless loop
    
with this fixture, tests on current head of master errors fail
with "Uncaught Error: ENAMETOOLONG, stat ...". Tests pass on
this branch.
apply requested style changes

- change named functions to anonymous inlined parameters
- change single return to three if/thens
Merge pull request #7 from isao/issue5

fixes yahoo/locator#5 improve logic to prevent walking sub-pkgs