[vala] (4 commits) Non-fast-forward update to branch wip/issue548

[Rico Tzschichholz <ricotz src gnome org>]

The branch 'wip/issue548' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  c0e6fcb... vala: Don't just guess and check for a matching base_interf
  09fffb7... vala: Search in all interfaces for an implementation match 
  f842e35... codegen: Do a proper check before connecting inherited impl

Commits added to the branch:

  182bc0c... vala: Don't just guess and check for a matching base_interf
  1023f90... vala: Search in all interfaces for an implementation match 
  52aa5b4... codegen: Do a proper check before connecting inherited impl
  4fdb44a... vala: Allow Method.compatible() to be used for expected fai