[librsvg] (16 commits) ...Merge branch 'limits'

[Federico Mena Quintero <federico src gnome org>]

Summary of changes:

  50b3a5f... limits.rs - New file; move the constant for maximum instanc
  f14b536... Rename num_elements_rendered_through_use to num_elements_ac
  2650d97... AcquireError: Add a MaxReferencesExceeded variant
  d0cbdbf... Do the limits check in acquire_node()
  7fb5175... Propagate AcquireError::MaxReferencesExceeded quickly upstr
  2151b3b... Add test for the billion-laughs equivalent from issue #515
  01c6184... xml.rs: Export a single xml_load_from_possibly_compressed_s
  197e7e2... XmlState: make a field private
  2c25647... Inline load_from_possibly_compressed_stream() into its sing
  e0beb49... Use a IsA<gio::InputStream> generic only in the toplevel li
  1869767... Rename ctx to user_data in the libxml2 callbacks
  ee6b6e1... Use Xml2Parser for the user_data of libxml2 SAX callbacks i
  74f2ca0... Call xmlStopParser() when the start_element callback return
  9a32e5e... Use the last error obtained in XmlState as the final result
  572f95f... (#515) - Add a limit for the number of loaded elements
  4458540... Merge branch 'limits'