Adds support for merging data from different archive types into the
database.

Minor bugfix on aggregation of week data to year resolution.

To merge data from different sources, add the follwing directive in
/etc/opt/openit/openit.cfg of the server:

LICENSE_DATABASE_REPLACEABLE $CONFIG_DIR/archive-replacement

In addition, create the /var/opt/openit/etc/archive-replacement file
containing lines of format:

<data type name>:<classification name>

The names must match those in acc_types, but with each caret
replaced by a space. There must be no extra spaces in the names.

Each line will specify which classifications of a data type should be
used as a basis for replacement of old data in the database. E.g:

Total license use v2.0:Product
Total license use v2.0:Package
Total license use v2.0:Feature

This will cause the backend to scan all "Product:Package:Feature" of
new data. If any of the found data matches with the old records found
in the database, these records will be replaced. The old records which
does not match with the new data, will remain in the database. The
"old" behaviour is to remove all old data. If there is no
archive-replacement lines for a data type, the old behaviour will
apply for this data type.

NOTE: The "Feature version" should not be specified in the
archive-replacement file.

NOTE_2: If a client is installed on the same host, patch #398 should
also be installed on 5.1 - 5.1.1.