set up structure for new occcam2d module

Signed-off-by: LK <LK@uni>
half way through...new structure for occcam2d module...

Signed-off-by: LK <LK@uni>
Merge branch 'lk.occam' of github.com:geophysics/mtpy into lk.occam
next step in occam2d: writing input files & updating parameters & reading config file
next step in occam2d: reading Edi files, writing datafile
reading occam data files done

Signed-off-by: LK <LK@uni>
writing datafile in progress

Signed-off-by: LK <LK@uni>
OCCAM2d Setup and data class working for setting up input files - merging of data files not implemented yet

Signed-off-by: LK <LK@uni>
start new version of calculating the mesh

Signed-off-by: LK <LK@uni>
mesh calculation ready - inputs look ok - check for side padding...

Signed-off-by: LK <LK@uni>
mesh/model building ok
removed artificial newlines for occam mesh/inmodel files
occam startup file - corrected missing colon
occam mesh file - corrected number of layers for proper bottom padding
occam input files - test runs ok
occam input files - included possible choice of frequency range or number of frequencies - both via parameters
occam input files - included choice of Tipper data
occam input files - switched from "both" to "tetm" key
occam input files - increased padding column width to 0.5* largest inter-station spacing
occam input files - print out info on profile and model length and depth