* Add some DB indices to make the /releases page much faster.

* Reduce the number of DB queries for the /all and /jobstatus pages.
* Show the Hydra version number.

src/sql/hydra.sql

@@ -401,3 +401,8 @@ create table ReleaseSetJobs (
     foreign key   (project, release_) references ReleaseSets(project, name) on delete cascade -- ignored by sqlite
     foreign key   (project, jobset) references Jobsets(project, name) on delete restrict -- ignored by sqlite
 );
+
+
+-- Some indices.
+create index IndexBuildInputsByBuild on BuildInputs(build);
+create index IndexBuildInputsByDependency on BuildInputs(dependency);