fix(extensions): CellExternalCopyBuffer onKeyDown event leak, fix #635

[ghiscoding]

fixes #635

[codecov]

Codecov Report

Merging #636 (c41254d) into master (501908a) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #636   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          153       154    +1     
  Lines        10281     10294   +13     
  Branches      3614      3615    +1     
=========================================
+ Hits         10281     10294   +13     

Impacted Files	Coverage Δ
.../app/modules/angular-slickgrid/formatters/index.ts	100.00% <ø> (ø)
...dules/angular-slickgrid/editors/dualInputEditor.ts	100.00% <100.00%> (ø)
...rid/extensions/cellExternalCopyManagerExtension.ts	100.00% <100.00%> (ø)
...angular-slickgrid/services/bindingEvent.service.ts	100.00% <100.00%> (ø)
...rc/app/modules/angular-slickgrid/services/index.ts	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 501908a...c41254d. Read the comment docs.