Fix ParsedTemplate to enable camelCase attributes

As for now, directive.Attributes is filled with "attName.ToLower()".

"Extract" method works on unchanged values and TemplatingEngine asks
for camelCase.

VisualStudio disregards the casing of parameters, so we can compare with
lower case.

This can be verified by using "linePragmas" attribute.

According to mhutch suggestion, fixed to use
StringComparer.OrdinalIgnoreCase.
Merge pull request #496 from PiotrZierhoffer/fixParsedTemplate

Fix ParsedTemplate to enable camelCase attributes