ENH: Use shapefile crs attribute when possible

[greglucas]

trafficstars

When reading in the shapefile, use the .prj file information if it is present to set a crs attribute on the reader which can be used down the line by features to get the correct Projection.

Somewhat interesting that loading the wkt from the file produces a different CRS than the one going through Fiona's CRS first... I'm not sure if that is expected or not, so opening this PR as a draft for now.

closes #2289

[dopplershift]

Seems really odd that those would be different.