Added Two Symbolic Icons and Added Info to Icon Extract Script

Added two new symbolic icons to "desktop/icons/hicolor/scalable/actions/
	-mypaint-close-tab-symbolic.svg
	-mypaint-tab-options.svg
Added Useage txt to "svg/symbolic-icons-extract.py" script to lessen confusion
Lastly, symbolic-icons.svgz has the two new icons mentioned earlier under Actions

Fixes #17
Revised Icons and Coded them In

  -Removed the Previous Symbolic Icons and added new Wrench Symbolic
Icon in Desktop/.../actions/ folder
  -Added "icon_name" perameter in def buttonless_button in
gui/widget.py
  -Coded the Symbolic icons in gui/workspace.py
  -Added Wrench Icon under Actions
  -Moved Rejected Symbolic Icons on the outside of
svg/symbolic-icons.svgz