Added Show, Eq, Read instances to LinearComic.
Added file reading feature for linear comics.

Comics.List.comics now reads in all comic
files from a given directory, reducing the dependence on hardcoded
crawling scripts.

Also wrote Fetch.ErrorHandling.filterErr (incomplete).
Removed unneeded imports.
CLI now reads comic list from script directory. Removed Comics module
Fixed Fetch.ErrorHandling.filterErr

Switched mconcat for mappend.