Merge pull request #4 from sightmachine/master

updating my repo
added getGrayArray

for use in canny edge detector
added canny operator

canny edge detector for simplecv-js
Merge pull request #5 from chaithuzz2/third

added canny
corrected errors
minor changes in threshold values
added a comment
Merge branch 'fourth' of github.com:chaithuzz2/simplecv-js into chaithuzz2-fourth