To run a single file, use:

  ruby -I test <filename>

http_proxy & https_proxy settings can now be specified with or without
the protocol prefix.

Make Geocoder.configure accept a hash (now preferred) and add
Geocoder.config method (for reading config). Deprecate old syntax.

Removed set_defaults from all tests and replaced with teardown to reset the defaults.

Signed-off-by: James McCarthy <james2mccarthy@gmail.com>