Add loops_gz config variable

This variable is going to be used to store the location of the loops file to
write. We have to add it to the config loading method to ensure it is loaded
properly.
Top level call for generating loop data

We need to export the loops so NDB can have loop annotations for all
structures. This provides the top level call to do so. We do it in the function
that exports interaction data since it seems to be the place to do this.
Move export to later in process

We should export once we have updated the loop annotations so we have the
correct loop data. This moves that call to after updating annotations.
Add first untested functions to write loop data

These functions are mostly and outline of what is needed to write out a csv
file of all loop annotations.
Use dicts not named tuples

We are deployed into 2.5, which lacks things like namedtuples. As such we have
to use dicts here instead.
Update main function to export loops

The main function may now export loops or interactions. It will look to see if
there is a method with the correct name, and if so run it.
Change loop export proceduce

We no longer attempt to add the information about motifs, we leave that to the
motif data. In addition, we have to translate the old style ids to new style
ids. We also need to have a method to get all pdb ids with loops.
Don't pass command line options to export

We just export all loops or interactions, without using the command line
options.
Some whitespace changes.
Clean up unused imports
Some flake8 cleanups
Another minor cleanup
Use index not name to access results
Check that we can generate a new style id

Seems that sometimes we may be missing new style ids. I'm unclear as to why or
how this could happen, maybe limitations of the dataset in dev. I dunno. Anyway
we should check for this and log a warning but still try to generate the file.
CSV writers have no flush method.
Write the header

Have to call writeheader to write the header in the csv file.
Force all fields to be quoted
The writeheader method is in 2.7

Since we are in 2.5 I can't use it. How annoying. In addition, we use the
writerows method as it is shorter.