Major Description
The value for Lambda in OnlineLogisticRegression seems not the be serialised/deserialised correctly.
If I train a model with a specific lambda value, serialise it, then read it back in, the value of Lambda goes back to the default value (1.0e-5).
I've created a patch that adds the lambda value into the write/readFields (org.apache.hadoop.io.Writable). Patch includes a unit test that checks the values after serialising/deserialising to/from a ByteArray.
I think this is correct, unless I'm missing something obvious?
Note: this patch is not backwards compatible - can easily adapt to be more backwards compatible if required.
