fully support non-spidered topics

[rahulbot]

The list of valid research use-cases for non-spidered topics is growing, especially in relation to multi-platform projects. Supporting topics with 0 rounds of spidering has been descried as an "accidental feature" to me, and researchers have noticed odd errors in non-spidered topics. One that comes to mind is seeing stories from sources not included the seed query show up in the topics. The research team would like us to take some time to check the code-path and support for this and make it more robust.