Added some more analysisdata unit tests.

Added some more analysisdata unit tests.

Added support for multipoint data to the analysis data testing
framework, and added some more tests for AnalysisData using it.

Also fixed a bug (found by the new tests) with frameCount() not being
properly updated for multipoint data.  The count is now kept by
AbstractAnalysisData, so derived classes no longer need to worry about
keeping it up-to-date.

Part of issue #823.

Change-Id: I672fbfb2ec5898b8118616574646f1432c7c0ce1