Fire window-created events for ElectronContainer at the end of the current event loop cycle

[bingenito]

The GroupWindowManager attaches events to new windows as they are created. The event for window created is fired and provides a window id. Electron has not registered the window internally yet when this event is fired so any attempt to get a reference to the Electron BrowserWindow instance from within the event handler via fromId does not work. The group manager is currently working incorrectly since an undefined window causes it to attach handlers to every window as though it is initial setup. This is causing duplicate handlers.

[codecov]

Codecov Report

Merging #179 into master will decrease coverage by 0.07%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master    #179      +/-   ##
=========================================
- Coverage   93.87%   93.8%   -0.08%     
=========================================
  Files          15      15              
  Lines        1338    1339       +1     
  Branches      223     223              
=========================================
  Hits         1256    1256              
- Misses         82      83       +1

Impacted Files	Coverage Δ
src/Electron/electron.ts	97.09% <0%> (-0.29%)	⬇️

[bingenito]

Coverage decrease is from addition of one line within a block of a few lines that was already not covered.