Redid spacing in GUI lab
OOP typofixes
redid spacing in ImgSegMST lab
Minor revision of the ImgSegMST lab.
Merge pull request #217 from insertinterestingnamehere/typos

minor revisions in the GUI lab and the ImgSegMST lab
Changed backend in matplotlibrc from gtkcairo to cairo
Merge pull request #218 from insertinterestingnamehere/matrcfix

Changed backend in matplotlibrc from gtkcairo to cairo