Release Name: 1.7

Notes:
As usual, just try 

sudo ./QUICK_INSTALL 

or 

./HOME_INSTALL.

It really should work.

This releases brings in some bug fixes and quite a few new features


Changes:
    Version 1.7 adds an option in legends for markers without any line;
just call save_legend_info with 'line_type' => 'None' in addition to
the marker information.  It is also now possible to give a 'legend' argument
to show_marker.  The value of the arg can be either a legend dictionary
or simply the legend text in which case defaults will be supplied for
the rest.  There is an example of this in samples/plots.rb
in the Legend_Outside figure.

    It saw a very significant improvement in that you can now query
the exact size of a text typeset by LaTeX, with the function text_size. Please
have a look at its documentation, and at the Text_size and 
Text_size_with_rotation samples in samples/figures/figures.rb.

    The code base was quite moved around so as to facilitate work on a 
Python version that would share as much code as possible with the Ruby one;
this should not bring user-visible changes (apart, maybe, from compilation
problems, but we hope not).

    Some bug fixes, including potential stack overflows (unprotected
snprintfs), and some new methods of Function. Dvector.fancy_read has been
reimplemented in C and benchmarked: it should be around three times faster
than before.