Deprecated rcParams validators

The following validators, defined in rcsetup, have been removed: validate_alignment, validate_axes_titlelocation, validate_axis_locator, validate_bool_maybe_none, validate_fontset, validate_grid_axis, validate_hinting, validate_legend_loc, validate_mathtext_default, validate_movie_frame_fmt, validate_movie_html_fmt, validate_movie_writer, validate_nseq_float, validate_nseq_int, validate_orientation, validate_pgf_texsystem, validate_ps_papersize, validate_svg_fontset, validate_toolbar, validate_webagg_address.

Stricter rcParam validation

rcParams["axes.axisbelow"] (default: 'line') no longer accepts strings starting with "line" (case-insensitive) as "line"; use "line" (case-sensitive) instead.

The rcParams["text.latex.preamble"] (default: '') and rcParams["pdf.preamble"] no longer accept non-string values.

All *.linestyle rcParams no longer accept offset = None; set the offset to 0 instead.