Implemented a wait dialog.

The wait dialog allows blocking tasks to show a progress form after some delay.
Fixed issue with SynchronizationContext.

SynchronizationContext.Current can become null without warning. There probably are more issues with this. An approach could be to create a service for this.
Wait cursor was not correctly restored with NiWaitDialog.

The wait cursor was not restored when the action completed before the timer of the form was started.
Improved platform newline handling.
Added TextBox and Label command bar controls.

Added a TextBox and Label to the command bar control set.
Moved the Text property from INiCommandBarControl to the controls themselves.
Implemented alignment on command bar groups.
Improved cross-AppDomain message processing.

Message processing over AppDomains has been improved. NiWindowHost class now also implements IsInputKey and IsInputChar to fix issues with text entered into textboxes interfering with mnemonics. Also cross domain message filters now work. Every AppDomain should have a message filter that broadcast PreMessageFilter requests over all AppDomains. Because of these changes, it is now possible to host NetIDE toolbars in forms in other AppDomains.