Cache hash should not use the config's absolute paths

[rogerntan]

We use the cache busting token functionality to ensure that new sprites are different. I just noticed that we were generating new sprites (and uploading them) even though nothing had changed.

It turns out that the image contents themselves are the same, but the configuration dictionaries differed. Each developer has a different repo path, and because some of the file paths in the configuration are absolute paths, the resultant hashes differed.

For us, we don't need the config to be an input to the hashing function, though I can see why it might be desirable. Would it be possible to use relative paths for the hashing function, or maybe a command line option to opt out of using the configuration dictionary for generating a hash?

Thanks!