Revert "Indexing blur test bench against toodee"

[gunvirranu]

Reverts #16. This removes all toodee related code from the test-bench suite.

Multiple reasons:

• toodee uses (col, row) indexing, so blur_by_index is probably just slightly slower than it could be
• toodee supports resizing, which isn't a use-case of this lib, so it's not exactly a good comparison
• The idiomatic blur using toodee doesn't seem too different from indexing, nor is it actually "nice" code

So there isn't much use to comparing with toodee. Considering comparing with imgref, but that's for later.