Adding support for case insensitive sorts

All sorting done within Spring Data is case insensitive.  On string columns, it is sometimes desirable to have this sort be case insensitive.  

In this particular change, I modified the Order class to allow an ignore case flag to be set so that case insensitive sorts could be supported.  This change works in conjunction with the change made for https://jira.springsource.org/browse/DATAJPA-296.

Issue: DATACMNS-281

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