Update App.config to fix "NET1.1 not found"

string::replace(installRoot, 'Framework64', 'Framework')
NET1.1 does not support x64 at all, therefore trying to read it from the registry does not work (if NET2.0 and above only, it would).
I dont know if it handles 100% of the cases, but it seems logical to me.
Merge pull request #101 from katlimruiz/patch-1

Update App.config to fix "NET1.1 not found" on x64 systems.