New LogicLib expression 'IsASubCommaUStr'.

Now it is possible to know easily whether a CommaUStr (Comma separated Unique
Strings) is part of other CommaUStr or, what it is the same, whether a
CommaUStr is a subset or substring of other CommaUStr.

This kind of comparisons is now possible

 ${If} "NetDiscovery,NetInventory,ESX" IsASubCommaUStr "$R0"
    ; True
    ...
 ${Else}
    ; False
    ...
 ${EndIf}
The suffix 'Tester' is not needed in these cases.
Change the macro for the LogicLib expression 'IsASubCommaUStr'.
Improve the command line parser.

These are the changes:

 * It is not based on the NSIS error flag.
 * The return codes are Unix-style.
 * There is a new LogicLib flag test '${CommandLineSyntaxError}'. This kind of
   comparisons is now possible.

     ${If} ${CommandLineSyntaxError}
        ; There is an error
        ...
     ${Else}
        ; There is not an error
        ...
     ${EndIf}

 * It is possible to use the new LogicLib flag test without call previously
   to '${GetCommandLineOptions}'.