1.7 release
Robustify against non-ascii in distro release name

Danke, Herr Schoedinger
Fix POD syntax
Make PURPOSE file optional

Consider absent "PURPOSE" file the same as an empty "PURPOSE" file,
don't put a warning as purpose text. Consider failure to read an
existing "PURPOSE" file an error, aborting journal initialization.
Fix a doc typo
Update doc paths to what we use for several years
Fix library search for weirder $0 values
rlRun: Robustify /dev/null usage

Previously, when a creation of a temporary file needed for some
operations failed, /dev/null was used instead. In these cases /dev/null
was propagated to places where it was passed to the user or even
deleted.

Now the failure is detected, reported and the features needing the files
are switched off for safety.
rlRun: Have LOG_LEVEL set in every case
Provide more information even for passed tests
rlService* functions provide more debugging information (BZ#908325)
Log service status when rlService* fails
Fixed packing first argurent (package name) in rlBundleLogs
Properly separate grep arguments and options
Update version to 1.8
Merge branch 'master' into journal

Conflicts:
	src/python/journalling.py
Implement persistent storage mechanism

Functions wanting to save some information persistently now have a
unified mechanism to do so. The underlying mechanism is based on Python
ConfigParser, and values can be stored under two levels of hierarchy:

  - namespace: for high-level distinction between e.g. function groups
  - section: for distinction of different types of values inside
    function group

rlFileBackup/Restore was migrated to this new mechanism