* Dispatcher reviewed and improved.
* Minor refactoring.
* XtermTerminalView initialization simplified.
* Additionally simplifying XtermTerminalView initialization.
* Replacing SemaphoreSlim with lighter TaskCompletionSource.
* Some async/await simplification.
* Resize locking mechanism in XtermTerminalView simplified.
* Resize handling improved.
* Trivial change in a code comment.
* After merge fixes, and some minor changes.
* DelayedAction fixed and some UI bug fixed.
* Removing TerminalViewModel.CustomTitleChanged event because it's covered by PropertyChanged anyway.