* man/amanda.8.in: explanation of incronly strategy.
* server-src/amadmin.c: recognize incronly strategy
* server-src/conffile.c: read the incronly strategy in the
configuration file.
* server-src/conffile.h: definition of DS_INCRONLY
* server-src/planner.c: Do planning for incronly strategy:
If the force flag is set perform a full dump, otherwise do
normal incremental processing but avoid full dumps.
* server-src/tapefile.c: Bugfix so only tapes which match
the regular expression for tape labels in the current
configuration are considered for writing.
