Remove the show button.

* src/manualRosetteDetect/rosettedetect_gui.m(show_Callback): Remove callback
method that serviced the show button.
* src/manualRosetteDetect/rosettedetect_gui.fig: Remove the button from GUI.
Calculate excess green and green chromatic coordinate.

* src/manualRosetteDetect/analyzeImgRosette.m(analyzeImgRosette): Use two new
methods to calculate exg and gcc.
(calc_gcc): New method that calculates green chromatic coordinate.
gcc = mean(G./(R+G+B)) where R, G and B are column vectors of red green and
blue values.
(calc_exg): New method that calculates excess green. exg = mean(2*G-R-B) where
R, G and B are column vectors of red green and blue values.
* src/manualRosetteDetect/rosettedetect_gui.m(vector_Callback): Create exg and
gcc matrices. Save them as gcc and exg.
Calc enclosing circle for every rosette.

* src/manualRosetteDetect/analyzeImgRosette.m(analyzeImgRosette): Make sure we
are using the calculated subimg and use the new method calc_diameter to
calculated enclosing circle diameter.
(calc_gcc): The gcc calculation should be gcc=mean(G)/(mean(R)+mean(G)+mean(B))
(calc_exg): Go back to using the mean for the exg calcs.
(calc_diameter): New method that calculates enclosing circle diameter.
* src/manualRosetteDetect/rosettedetect_gui.m(vector_Callback): Accumulate
diameter values and save them to diams.
* src/manualRosetteDetect/minboundcircle.m(minboundcircle): New file
containing logic to find the minimum boudning circle for any given list of
points.