findSequencesInList drops a result when using same basenames with and without frame placeholder

[justinfx]

Given the following:

>>> findSequencesInList(['file02.txt', 'file.txt'])
[<FileSequence: 'file2@@.txt'>]

The result drops the single "file.txt" because it has a similar basename to "file02" without a frame placeholder. We would expect to see 2 different sequences:

[<FileSequence: 'file2@@.txt'>, <FileSequence: 'file.txt'>]

[justinfx]

The problem occurs because there is a key collision when it builds up a list of frames, between "file02.ext" and "file.ext". Once "file02.txt" establishes the key and adds its frame value, "file.ext" is discarded because it does not provide a frame.
The fix is to make the key more unique to differentiate between paths WITH and WITHOUT frames. This allows "file.ext" to be treated as a different single frame sequence.

[justinfx]

I've verified that this is not an issue in https://github.com/justinfx/gofileseq