Explicitely add lpthread LDFLAGS for submitclient.
Update autoconf macros from upstream.
Display dj-setup-database usage on every error.
Executables now have a type.

The type is one of compare, compile and run. One can view and edit the
type in the web interface but it is not used somewhere (e.g to filter).
Filter executables by type for selects.
Fix list of problems/languages where one executable is used.
Add config checks for executables.
Check on post_max_size in REST API.

The comparison of post_max_size and $_SERVER['CONTENT_LENGTH'] allows
us to give a better error message when a judgedaemon posts too much
data in a single request.
Fix copy/paste bug in dj-setup-database.