Hide PolyModel inheritance_line bookkeeping property from the User Profile form.

Use the LINKNAME_PATTERN from its new home in key_name.py. Also, add some missing blank lines that are required by the style guide.

Add lots of new functions to key_name.py, including path/link_name processing. Copy various link_name related regex patterns to key_name.py and use them. Add error checking that raises a key_name.Error exception when name...() functions are given empty arguments. Hard-code class names, since they match what was typed into the module.class.__name__ to get the name anyway. This eliminates dependencies on any modules by key_name.py.