Fix animation functionality

Improve abstraction and encapsulation, makes threading more obvious.

*** This commit is tied directly to changes in the vistrails repository
(branch uvcdat-490-animation-updates).  Both branches need to be
used/merged. ***
Fix playback state logic
Enable uvcmetrics to be built from git
Removed support for 10_6 and 10_7 Mac support
Merge branch 'update_uvcmetrics'
Merge branch 'remove_mac_106_107_support'
Ok this should not look for qt when not building gui
removed xrtra line that caused failure on sample data
Merge branch 'xtra_line_at_End_of_sample_file'
moved GUI bit at the right place in cmakelist
Merge pull request #140 from charlesdoutriaux/issue_554_no_gui_no_qt

moved GUI bit at the right place in cmakelist
Merge remote-tracking branch 'devel/issue_554_no_gui_no_qt'
Merge remote-tracking branch 'devel/issue_534_ctest_fails_and_add_vcs_tests'
setup script changes
almost there using vtk instead of matplotib
Got check image to use vtk reader instead of mpl, exact same answers as before
Merge pull request #147 from charlesdoutriaux/img_diff_from_vtk

Got check image to use vtk reader instead of mpl, exact same answers as ...
reindented test otherwise unmergeable
Merge remote-tracking branch 'devel/img_diff_from_vtk'
@jbeezley string could not be split as you set it up (with \) so I tweaked it a bit. I like how you test if path actually exist before setting to a PATH