Add "Settings Location" option to the Options dialog.

Add 'DisableUpdateUI' setting that if True hides the 'Check for updates...' menu item and the update related Options in the Options Dialog.

Github issue 178, 'update available' check was broken. Fix standalone installer so install location is shown in the appwiz.cpl control panel. Fix lots of bugs in the find/replace logic to do with multiple matching words in a single node value