export to ER-Mapper has positional errors and cannot be read by ER-Mapper

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The ER-Mapper format as written by Biodiverse will not be imported into
ER-Mapper 2010.  Oh the irony.

This seems to be mostly due to ER-Mapper being a "fussy eater" WRT header
files.  ArcGIS and Erdas Imagine 2010 don't seem to care so much.

There are also errors in the headers and coordinates.  Corrections are below.

LastUpdated header needs to be for GMT (or possibly contain the timezone)
LastUpdated = Thu Jun  3 07:52:35 GMT 2010 

CoordinateType should be EN
CoordinateType  = EN

NullCellValue should be immediately after CellType line

The registration coord given in the file is for the cell centre, not the
corner.  
    RegistrationCellX  = 0.5
    RegistrationCellY  = 0.5

The coordinate space needs to change, but choosing a bizarre default
crashes Erdas.  Best to use "RAW" datum and projection and advise users to
edit the header before using the file in ER-Mapper, assuming it is used
less often than the others.

    CoordinateSpace Begin
        Datum       = "RAW"
        Projection  = "RAW"
        CoordinateType  = EN
        Rotation        = 0:0:0.0
    CoordinateSpace End

Original issue reported on code.google.com by shawnlaffan on 3 Jun 2010 at 8:32