Creating a dialog for color thresholding filter

Conflicts:

	glviewer/static/viewEditMenu.js
	glviewer/templates/view.html
Update button
Client side Scar ratio plugin object

Conflicts:

	glviewer/static/viewEditMenu.js
HSV and color histograms

Post canvas image when the filter is initialized WIP

HSV and color histograms
HSV plots with border for hue
Ready for HSV plots
Parameter to specify output format
xlimit and proper scaling
Moving the incoming sandbox image_historgrams to its location
Able to accept the canvas image on server side

Conflicts:

	glviewer/static/viewEditMenu.js
Processing the current canvas image and sending out the histograms each time
Able to write opencv output to buffer
Updating current values in the filter object
Thresholding the image

Thresholding the image

Invoking get_mask with correct parameters
Scaling hue for opencv
Adding test for creating image transparency
First workflow ready
Refactor to a separate plugins folder

* Load the plugin only when required
Merge branch 'dev/dj-color-threshold-2'

* dev/dj-color-threshold-2:
  Refactor to a separate plugins folder
  First workflow ready
  Adding test for creating image transparency
  Scaling hue for opencv
  Thresholding the image
  Updating current values in the filter object
  Able to write opencv output to buffer
  Processing the current canvas image and sending out the histograms each time
  Able to accept the canvas image on server side
  Moving the incoming sandbox image_historgrams to its location
  xlimit and proper scaling
  Parameter to specify output format
  Ready for HSV plots
  HSV plots with border for hue
  HSV and color histograms
  Client side Scar ratio plugin object
  Update button
  Creating a dialog for color thresholding filter