Added custom copytree method which doesn't care about existing directories.
Switched to use utils.copytree instead of shutils.
Added formatted dictionary type.  This will be used to store the context.
Replaced context dict with context formatted dictionary.
Removed direct formatting
Changed install to use a formatted URL rather than prefix plus package name.
Formatted paths.
Added call to .format for paths used by ConfigInstaller.
Added tests for format with out_of.
Modified hash test so that it handles sha1 output from shasum.