* xmlrpc usage encapsulated
* utility functions grouped
* UI and Operators separated
* Encapsulate exceptions

As with previous commit, this version now utilizes the new way
of storing user credentials, making it a lot easier for users
to use the uploader in subsequent usages.

Note that refreshing the session list isn't done on login anymore
so remember to press that button :)

[[Split portion of a mixed commit.]]

this commit also makes a minor change with path joinin in preset_utils.py

Got the wrong presets path on some windows installations, should work now. (also thanks to jesterKing and testscreenings)

- was catching the user script path instead of the install script one