parse with NumberFormatInfo.InvariantInfo everywhere

closes #5240
fix trailing comma
remove unused OpenRA.Server extensions
StyleCop
new shorthand Exts.(Try)ParseIntegerInvariant
Merge pull request #5262 from Mailaender/parse-invariant-culture

Added checks for NumberFormatInfo.InvariantInfo everywhere
Fix warning message when compiling under Windows (MSBuild/VS).
Merge pull request #5303 from reaperrr/win-warnings

Fixes warning message when compiling under Windows (MSBuild/VS)
Fixes #3036

See also #5149, #5191