* Update the Scour extension (scour.inkscape.py) to work with recent versions of the scour module (0.30 and later)
  (https://github.com/codedread/scour/)

* Strip the Scour module from Inkscape source code and use an external copy of instead (i.e. make it a requirement). This avoids any potential license issues with the Scour module's Apache license 2.0

* Update Scour extension dialog (scour.inx)
  - add new settings added in Scour versions 0.29-0.31
  - attempt to arrange/group settings intuitively
  - convert "help" tabs to individual tooltips for each setting

This also fixes bug #748639 since the overall height of the dialog is reduced by splitting settings across three tabs and removing the "Help" tabs (they caused the increased dialog height since they contained a huge amount of text)

Fixed bugs:
  - https://launchpad.net/bugs/1411149
  - https://launchpad.net/bugs/748639

(bzr r14574.1.1)