Collective.xmltestreport

------------------

- Make sure errors in layer teardown don't prevent the test report from
getting written.
[davisagli]

------------------

- Revert "Exclude system site-packages from tests' sys.path". This commit
changed the API/output of collective.xmltestreport in a minor version without
mentioning. This essentially broke all Jenkins jobs out there including all
Plone coredev jobs and all the packages/code that relies on that output.
[timo]

------------------

- Add missing dependency to z3c.recipe.scripts
[ggozad]

------------------

- Exclude system site-packages from tests' sys.path'
[Andrey Lebedev]

------------------

- Fix import errors problem (TypeError) introduced in 1.2.5.
[jone]

------------------

- Handle startup failures (import errors) and expose them in the testresults.
[jone]