[Feature] Support for zip file processing

[bralax]

Most transit agencies support gtfs which is the protocol google created to handle the processing of transit information. There are two parts of the system. Real-time data which is transferred via protocol buffers and gtfs static which is exposed as a zip file. The minimal needed to use this data for a Tidbyt app is the static zip but to do that we need the ability to parse zip files.

Context: I built a community app for the Long Island rail road. It relied on a secondary file that the MTA provided that took the zip and converted it into json. They got rid support for that file on the ground that developers can get the same data from the raw zip.

[mattbroussard]

This and a lot of other useful functionality could be added relatively easily by making starlib available to applets.

[mattbroussard]

Actually, it looks like several other starlib modules are already included, including gzip (but not zipfile)

[dinosaursrarr]

I had a commit for adding the zip file module to pixlet for something else I never finished (which was also about gtfs). Have created a PR in case any one else would find it useful.
#826