SatelliteResourceLanguages does not support comma delimiters

[martincostello]

The SatelliteResourceLanguages property raises errors if commas are used to delimit the values. For example:

<SatelliteResourceLanguages>en,en-GB,en-US,qps-Ploc</SatelliteResourceLanguages>

MSBuild processes the values and behaves correctly if commas are used, so a warning should not be raised if they are used instead of semi-colons.

[mhutch]

This one is documented as semicolons and there is no standardized splitting behavior for properties, as that's up to the tasks that use the properties. I'll update the schema to match actual behavior.