npgsql - Npgsql2: Added tests for date and infinity comparisions.

Log Message:
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Added tests for date and infinity comparisions.

Thanks Andrus Moor for heads up and test case.

Modified Files:
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Npgsql2/testsuite/noninteractive/NUnit20:
CommandTests.cs (r1.20 -> r1.21)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/npgsql/Npgsql2/testsuite/noninteractive/NUnit20/CommandTests.cs.diff?r1=1.20&r2=1.21)