Consistently use difftime function.
Only try to update menu entries when they exist.
Improve judgehost load display:
- add 2 minute load and order in increasing length, like 'top'
- use fixed time for now()
- include judgings that overlap partly with start of interval
Display language/problem name instead of ID.
Also install flot and ace JS files.
Rename SQL upgrade script to released version.
Update changelog for 4.0.0 release and add 4.0.0RC1 release date.
Prepare for 4.0.0 release.
Continue development.
Also install auth/ subdir and genrestapicredentials.

Thanks Glenn Martin for the report.
Mention default admin password in het manual.

Thanks Glenn Martin for reporting.
Remove checks for bisonc++/flexc++ from configure and add their
versions to generated files at time of generation.

Bisonc++/flexc++ are only needed during 'make dist' which should
never need to be run by users installing the system. Also at 'make
dist' we have no configure yet, so we cannot depend on using
etc/config.h for storing version information.
Fix d003189d: create www/auth directory before installing files there.
Cleanup all processes before exiting

This should prevent forkbombs or other weird cases where a process has
detached itself from runguard and doesn't get killed normally.
Only execute JSONcpp library check when building submit client
and throw errors when required libraries are not found.
Add git to list of required packages for development.
Add SQL structure for contest-problem many-to-many mapping.
Add problem 'hello' to demo practice session as well.
Uniform layout of SQL example data.
WIP: change SQL queries on probid.