re #84

Homebrew's glibmm uses deprecated bits of glib:

  CXX      Render.o
In file included from Render.cc:16:
In file included from ./Render.h:23:
In file included from /usr/local/Cellar/pangomm/2.42.0_1/include/pangomm-1.4/pangomm/layout.h:31:
/usr/local/Cellar/glibmm/2.60.0_1/include/glibmm-2.4/glibmm/object.h:73:3: error: 'GParameter' is deprecated [-Werror,-Wdeprecated-declarations]
  GParameter* parameters;
  ^
/usr/local/Cellar/glib/2.62.0/include/glib-2.0/gobject/gparam.h:194:39: note: 'GParameter' has been explicitly marked deprecated here
typedef struct _GParameter      GParameter GLIB_DEPRECATED_TYPE_IN_2_54;
                                           ^
/usr/local/Cellar/glib/2.62.0/include/glib-2.0/glib/gversionmacros.h:770:49: note: expanded from macro 'GLIB_DEPRECATED_TYPE_IN_2_54'
# define GLIB_DEPRECATED_TYPE_IN_2_54           GLIB_DEPRECATED_TYPE
                                                ^
/usr/local/Cellar/glib/2.62.0/include/glib-2.0/glib/gmacros.h:1013:30: note: expanded from macro 'GLIB_DEPRECATED_TYPE'
#define GLIB_DEPRECATED_TYPE G_DEPRECATED
                             ^
/usr/local/Cellar/glib/2.62.0/include/glib-2.0/glib/gmacros.h:942:37: note: expanded from macro 'G_DEPRECATED'
#define G_DEPRECATED __attribute__((__deprecated__))
                                    ^

https://github.com/Homebrew/homebrew-core/issues/37873

fixes #55

automake isn't strictly necessary if building from a tarball.

It was a long-winded way of writing autoreconf -si.

fixes #19

The old version still exists in the old/ directory for the time being.

This introduces a dependency on Filesys::Df
  http://search.cpan.org/~iguthrie/Filesys-Df-0.92/Df.pm
  apt-get install libfilesys-df-perl