[librsvg] (22 commits) ...Update dependencies

[Federico Mena Quintero <federico src gnome org>]

Summary of changes:

  cd84843... librsvg_crate: New crate; this will be the public Rust API  (*)
  a0feaec... Provide a minimal loading API in librsvg_crate (*)
  fbeece2... Handle: don't take &mut self where &self will do (*)
  8bb244d... Add a CairoRenderer and an SvgHandle::get_cairo_renderer()  (*)
  648fcc8... CairoRenderer: add get_dimensions() method (*)
  3939feb... librsvg_crate/examples/render.rs - Basic rendering example  (*)
  254452d... librsvg_crate: Add a build.rs to find libcroco via pkg-conf (*)
  4357053... rsvg_error_quark(): Port to Rust (*)
  4df0ef3... Turn most g_warnings into panics, and don't use g_warning() (*)
  ddc2fd1... Don't use str.trim_left/right, use trim_start/end, bump Rus (*)
  bf9d061... Use libxml's structured error callback instead of vararg on (*)
  40ff041... LoadOptions: add an unimplemented read() method (*)
  e04893e... LoadOptions: add a read_file() method (*)
  46c97e7... LoadOptions: add a read_stream() method (*)
  cd9d2cb... CairoRenderer: add a get_geometry_for_element() method (*)
  e4b629a... CairoRenderer: add a render_element() method (*)
  3953989... LoadOptions: remove the base_url option (*)
  7ffd9b8... First pass at the librsvg crate's documentation (*)
  ff0c33f... Add toplevel docs for librsvg_crate (*)
  b02b26a... Merge branch 'rust-api'
  97dbaf3... Remove unused imports
  c414d17... Update dependencies

(*) This commit already existed in another branch; no separate mail sent