[vala] (7 commits) ...codegen: Don't use temp variable for stack allocated simple type assignment

[Rico Tzschichholz <ricotz src gnome org>]

Summary of changes:

  90b0ae5... build: Add --enable-debug configure option (*)
  47dbec4... codegen: Replace if-else-tree with switch (*)
  71d7992... vala: Minor clean up assignment to binary expression transf (*)
  1058066... tests: Extend assignment and array element access tests (*)
  bccc3ac... codegen: Don't emit unused temp variable for element access (*)
  e701142... vala: Don't replace assignments for local variables with no (*)
  32ffc86... codegen: Don't use temp variable for stack allocated simple (*)

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