[geary] (9 commits) ...Make client classes unit testable. Fixes Bug 776421.

[Michael Gratton <mjog src gnome org>]

Summary of changes:

  b7224d6... Stop cmake warning that we are using an internal target nam (*)
  e0b1c7b... Make VAPI build source arg a common valac arg, rather than  (*)
  2f23f92... Don't duplicate gthread library when linking. (*)
  403c50a... Add webkit to the list of client packages, so it can be re- (*)
  ef46102... Rename "geary-static" to "geary-engine" to better reflect w (*)
  bf42b7e... Split the client binary build up into a static lib + final  (*)
  325232b... Add client lib to the test build. (*)
  50120c6... Add simple/demo client unit test using GSettings. (*)
  f7af75f... Make client classes unit testable. Fixes Bug 776421.

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