* fitfile(.fit.mat) format

This file preserves raw positions(digitizer, meg) measured by measurement device.
Format is below.
File accessor is stored $POSITIONING/file_accessor/fitfile

header
    .file_type           : file type    [string] = ('FIT-MAT')
    .version             : file version [double]
    .face_file_name      : face filename [string]

mri_key                  : MD5 hash key made from analyze image file(*.img) [string]

digitizer                : This structure has a data which is measured by digitizer.
    .coord_type          : coordinate system of measured data [string] = 'digitizer_Right_m'
    .trans_mri           : affine transform matrix [4x4 double]
                           from digitizer to MRI coordinate system.
    .landmark
        .lpa             : Left  preauricular [1x3 double]
        .rpa             : Right preauricular [1x3 double]
        .nasion          : Nasion             [1x3 double]
    .head
        .pos             : point list on head [Nx3 double]
    .face
        .V               : face vertex coodinate [Nx3 double]
        .F               : face patch index      [Nx3 double]
    .marker_on_digitizer : MEG marker position on face(measured by digitizer).
        .name            : marker name list   [Nx1 cell]
        .pos             : marker positions   [Nx1 double]

sensor                   : sensor position data in the hardware space 
                           (measurement system dependent)
    .coord_type          : coordinate system of pos. [string]
                           MEG : 'Unknown'
                           EEG : 'digitizer_Right_m'
    .name                : sensor name list [Nx1 cell]
    .pos                 : sensor positions [Nx3 double]

marker_on_meg            : marker position measured by MEG
    .coord_type          : coordinate system of pos. [string] = 'Unknown'
    .name                : marker name list [Nx1 cell]
    .pos                 : marker positions [Nx3 double]
    .trans_mri           : affine transform matrix [4x4 double]
                           from MEG coordinate system to MRI coordinate system.
