fixed bug in estimating skin depth in ws3dinv and modem
Merge branch 'master' of https://github.com/geophysics/mtpy
fixed bugs in modem.Data when writing data file and period list is given, and in modme.Model renamed strike_angle mesh_rotation_angle
Merge branch 'lk.degminsec'
commented out one occasion of MAX LINES in info section

Signed-off-by: LK <LK@uni>