Add support for EWKB geom format
Geometry format improvements.

Adds EWKB format. Adds hex WKB/EWKB format. Adds test for (E)WKB.  Adds valid
geometry check for WKB linestrings. Reset factory internal string if exception
is thrown.
Add before/after_changesets calls to handler
Improved text output for coordinates.

There is a basic function now in the location class that can output coordinates
to an output iterator. It uses 7 digits after the decimal points or less if
they are 0. This is now used by the wkt factory to create minimal length output.
Tests are provided.