[librest] (10 commits) Non-fast-forward update to branch wip/baedert/fixes

[Timm Bäder <baedert src gnome org>]

The branch 'wip/baedert/fixes' 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:

  0531cca... tests/threaded: Stop using g_thread_create
  2730be8... RestProxyCall: Remove unused struct
  803fa43... RestProxyCall: Make sure _sync reliably sets error_out
  f4ff5d8... RestProxyCall: Add documentation for _sync
  6186931... tests/threaded: Stop using deprecated libsoup API
  ca2c493... RestProxy: Don't leak the soup session
  6ed51db... tests/threaded: Use GTest

Commits added to the branch:

  9ed72ed... build: Set explicit version requirement on libsoup (*)
  8f904a8... proxy: Remove use of libsoup-gnome (*)
  3cb5458... tests/threaded: Stop using g_thread_create
  5b66d2c... RestProxyCall: Remove unused struct
  80efc32... RestProxyCall: Make sure _sync reliably sets error_out
  d300e04... RestProxyCall: Add documentation for _sync
  57c9910... tests/threaded: Stop using deprecated libsoup API
  ceafacc... tests/threaded: Use GTest
  dfaefa7... RestProxy: Remove unused session_sync
  75b9559... tests/proxy-continuous: Use GTest API

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