fix: Texture slots for world and materials

fix: Orthographic and perspective camera view angle thanks to Iari Marino
add: some numpy functions to export mesh possibly faster in next version
fix: parametric surfaces much accelerated and now actually usable (max gradient defaults were wrong from the time of their implementation in most pov literature. Thanks to William F. Pokorny for finding this out!
add: very basic "blurry reflection" hack for when using plain official POV
add: push of (as of yet badly formatted) feedback to interactive console
add: POV centric workspace, default when addon is left activated from previous session.
add: Sound signal support on finished render (set from addon preferences)
add: support for pov 3.8 and decremented in a few areas, waiting for the release
add: freestyle interface with convoluted workflow currently but preparing for next release.
fix: commented out Charset feature because POV 3.8 auto detects encoding
fix: a few dot notation look ups aliased and removed
fix: restored some more removed properties from 2.79 ( a few remain to do)
fix: texture mapped specular max value increased
fix: faster defaults for radiosity
fix: many default texture influences switched to 1 because boolean enabling is required anyway so 0 was a bad default
fix: some icons were missing since 2.8
fix: some formatting improvement was started