Add support for additional non-standard metadata files

.prj

No manipulation of projections, only simple read/write of ESRI WKT strings. Probably means reading contents of prj file into a Reader .prj attribute. And adding a .prj attribute to the Writer, which gets written to a prj file on close().

.cpg

Non-standard but commonly accepted file that specifies which text encoding to use, can solve problematic cases.