Support setting url in config

Currently we have localhost hardcoded in the service file. This patch makes it
to default to localhost, but let's people override the url in config file. Thus
changing URL doesn't need changing service file.
Let worker report real hostname

Getting rid of hardcoded 'localhost' constant and using real hostname.
Merge pull request #20 from miska/master

Support setting url in config
Redo documentation

Document how to get some instance up and running and start the other sections
of documentation as well. No more one big document, but several separate
documents.
update apparmor profile for git push enabled and .thumb dir
Merge pull request #28 from nilxam/update_apparmor_0411

update apparmor profile for git push enabled and .thumb dir
Merge pull request #27 from miska/master

Redo documentation
use _rowid_ to make triggers also work on tables without primary key 'id'
print error more obvious and exit with 1
don't restart job if it's missing files, eg iso image
Merge pull request #30 from lnussel/pr_misc

misc fixes
make sure essential fixtures are applied by checking job states
add details link also for scheduled jobs
allow to change prio in details view
add statement how to trace sql
introduce assets
register iso as asset on job creation
increase version
asset download stub for webui