Fixes for librsvg

[Jehan Pagès <jehan marmottard gmail com>]

Hello,

According to librsvg webpage, development discussions about this
library are to be held here.
I am one of the GIMP developer, and we have used librsvg already for
some time. But lately we are working on vectorial icons and I wanted
to use librsvg for icon extraction from a single source file. But I
have had a bunch of issues with it. One of these is that librsvg
returns int dimensions and positions (dimensions actually also have
double values, but these are made out of the int values, which make
them useless. Positions are only int).

I have just uploaded patches for this issue in order to get useful
double values: https://bugzilla.gnome.org/show_bug.cgi?id=762039
Could these be reviewed upon? This would really help me (and GIMP!).
If you tell me these are good, I can push the commits you validate.
Thanks.

Jehan