Update to latest bootstrap.py

Downloaded from http://downloads.buildout.org/2/bootstrap.py
fix(findcode): better finding of test code

This fix sorts the --paths to look for code.
Longest paths come first. This is for cases where
one checks out other sources within his source directory.
In such a case this structure can happen:
my_package
my_package/src/some_other_package

Now when my_package gets found first. It logs an import
error and then goes on.
by sorting with longest paths first. I always get the most
specific match first. Since the loop is short circuited here,
it will never look at my_package.

This fixes #15
Beginners mistake
Faster Travis CI builds

See http://docs.travis-ci.com/user/workers/container-based-infrastructure/
revert the wrongly changed test code
Move sorting to different location
Merge pull request #16 from zopefoundation/nested

Correctly deal with overlapping --test-path arguments

Fixes #15
Update to latest bootstrap.
Note blockage of 'pypy3' support.

Waiting for release of fix (already committed) for:
https://bitbucket.org/pypy/pypy/issue/1946/cursesinitscr-raises-ctype-typeerro
order layers by MRO before doing topological sort
Adding tests