Handle missing values in data sets

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From loading through the SOM algorithm, IFC Soft should allow data points to 
have missing values. Currently, when reading a file, if it finds a missing 
value, it throws out the data point.

In the SOM algorithm, if a value is missing, the data point can still be placed 
based on the dimensions it has, and it should then only modify those dimensions 
which it has.

For WRCs, perhaps the wedge could be given a size of 1/2, but somehow be marked 
as N/A.

Original issue reported on code.google.com by kyle.tha...@gmail.com on 13 Apr 2011 at 8:13