Build process: ensure that Ride can be built without the need to access any Dyalog private/internal repositories

[dyaandys]

At 0978c51

There are references to some of Dyalog's private repositories which should be eliminated. Additionally there are some icons that should be added to Ride source, rather than being checked out from elsewhere.

Additionally on Windows we currently use a private copy of rc.exe - we should pick up what is in the Microsoft SDKs.