Remove magic numbers

[motiwari]

Magic numbers are an anti-pattern -- it makes code hard to read, and requires every instance for the magic number to be updated if it should be changed.. It's better to move these to a constants.py file and import them everywhere.

Examples

[d1ngn1gefe1]

These magic numbers mainly show up preproc. The preproc directory is only needed for data pre-processing and should be made internal/private.

@zanedurante @linden-li Shall we create a separate GitHub repo? Is there a better way of making some directories private.

[linden-li]

@zanedurante @linden-li Shall we create a separate GitHub repo? Is there a better way of making some directories private.

Yes, we can create a separate GitHub repo for data preparation and cleaning. We'll be releasing the cleaned annotations publicly anyway.

[linden-li]

@d1ngn1gefe1 Making this as done, since you made them private variables.