New tests for new start/status/stop scenarios. These tests allow for
running more than one crawler on a machine in different "contexts".
This requires that each crawler's pid file and exit file be unique. So
these will now be specifiable in the config file. The old default
values will also be honored, which means that we can start crawlers
with conflicting pid files and/or exit files.
New tests for process management in /tmp/crawler.
Track context of running crawler. To support this, moved pidfile to
/tmp/crawler (created on the fly if needed). This meant that the
application must write out the pidfile since daemon.py does not have
all the information needed. Also added tests for make_pidfile() and
running_pid().
Only define the pid directory in one place, in class CrawlDaemon.
Merge branch 'context' into devel