Added PlaceRectangle, NumberThreshold, CountContours, and Crop Operations

[jaxnb]

Place rectangle places a red rectangle between two points.
Number threshold returns a Boolean by running a number through a threshold.
CountContours returns a number of how many contours are in a contour report.
Crop can crop an input mat.

[codecov-io]

Current coverage is 52.13%

Merging #529 into master will decrease coverage by -0.03% as of 8705cb1

@@            master    #529   diff @@
======================================
  Files          134     138     +4
  Stmts         3997    4072    +75
  Branches       438     439     +1
  Methods          0       0       
======================================
+ Hit           2085    2123    +38
+ Partial        118     116     -2
- Missed        1794    1833    +39

Review entire Coverage Diff as of 8705cb1

---

Uncovered Suggestions

1. +0.52% via .../ExceptionAlert.java#83...103
2. +0.37% via ...cketPreviewView.java#88...102
3. +0.37% via ...indowController.java#219...233
4. See 7 more...

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[WPIRoboticsProjects-Bot]

Issue found: Avoid unused imports such as 'org.bytedeco.javacpp.opencv_imgproc.rectangle'

[AustinShalit]

This PR has grown stale. Please reopen with updates and we will take another look.