Disable selection list instead of replacing it by hidden input if
there's only one element to keep labels to input be valid HTML.
Check for flexc++ and bisonc++ and save versions in config.h.
Fix compile error in checktestdata.

Bisonc++ >= 4.02.00 doesn't work with old generated headers
since exceptionHandler is missing.

Flexc++ >= 2.00.00 doesn't work with old generated headers
since postCode is missing.
Include default compare script into database.
Include default float compare script into database.
Directly call command line scripts.

This fixes a potential race condition when running multiple
judgedaemons, where one judgedaemon overwrites the symlink by another
judgedaemon. Also scripts now know can determine their own path.
Directly call compare scripts.
Directly call run scripts.

Also include default run script in database. If existent, the runjury
executable is copied next to the run executable (including the
additional support program runpipe).
Default run/compare script is now configurable.
fetch_executable always returns execrunpath.

It's not longer necessary that calling functions need to know if the
executable is new or not. This cleans up the code a bit.
No script is considered as 'special' for the judgedaemon.

The judgedaemon can handle the compare/run scripts without knowledge
about its type (default or special).
Cleanup from old files.
Add checks for non-existing default compare/run scripts.
Fix copy/paste bug in executable upload code.