Updated installer that handles upgrades better

[meppyman]

OK I never look forward to upgrading as I always forget what I did to make it work properly last time, what features I installed, etc. The installer seems to be custom built, not sure why a standard one isn't used? Time for an upgrade?

Here is my brief wish-list for the installer:

* Tell you at the start of the install if there are any services or programs running that need to be stopped, and then let you retry with the settings you have selected (or warn before you make any selections) - currently it only tells you right at the end if there was an error then it quits and you have to start again and get all the options right all over again

* When upgrading read from the previous install settings and present those as options for the upgrade so that I don't have to check what options I installed last time

* Have an option that has the recommended settings for the RCC PC (i.e. not HM, Web or Telnet services).