Additions in LAS 3

Things I have to look out for:

• parameter zoning - values in HeaderItems can now be arrays e.g.

  NMAT_Depth[1].M 500,1500 : Neutron Matrix Depth interval {F}

• Extend HeaderItem to include format= and association=

  format should probably be left as is and then used when parsing data - special cases will be strings, datetimes, and DMS location data. Strings will need to be read as is, datetimes parsed to datetime objects, and DMS converted to decimal degrees.

  assocation should be a list of either the associated HeaderItem, or, if that doesn't exist, strings. It has to be a list because there can be multiples:

  NEUT .V/V : Neutron Porosity | MATR[1], MATR[2]

• Data section name. Ideally I think it's meant to be ~SECTNAME_Data | SECTDEF where again the | indicates the data section SECTNAME represents that defined by SECTDEF. But in practice I suspect this is not reliable, so probably best to assume SECTNAME == SECTDEF and just parse this pattern where it exists and use it to construct the LASFile.data_sets dictionary.

• Automatically turn lots of curves e.g. TT[1], TT[2], ... TT[n] into a single TT CurveItem with 2D data array.