Leginon

It looks like the call to close the window from the button "Continue" which serves two functions creates a recursive loop during closing. On some systems it is resolved by the system but on others it is stuck.

r15322 solved the problem with two separate buttons one continue next alignment and one to close the window. Also noticed that leginon program not exiting properly after using align-presets dialog once alignment is made. Change to use Dialog.Destroy() instead of Dialog.EndModal() to close the thread properly when the program exit. Unfortunately, as a result, the align preset window will not retain the last changed image viewer parameters when reopened.

Will not merge to branches for now until local users agree that it is not too inconvenient.