Fix config, two/three joint arm, and osc bugs

[studywolf]

Fixed up a few bugs found in the two and three joint arms

Fixed up a few bugs in the config

• orientation for the Jacobians was being calculated incorrectly
• centrifugal and Coriolis forces were calculated incorrectly
• removed c and S, replaced with partial effects C
• removed orientation, replaced with R

Fixed a bug in the osc code with vmax=None where kv wasn't included

Added pytests to test the symbolically generated equations in the config using two joint arm equations analytically derived in (Spong et al, 2004)

Added an update_display option to the PyGame interface

Updated all the examples to only update every 20 time steps, super speeds things up

[p3jawors]

LGTM