libcollectdclient: Add an implementation of the network encoding.

Only support standard values for now, but notifications and the security
features will be added later.
libcollectdclient: Move the header files to a subdirectory.

This makes it easier since the header files depend on one another.
(At least they will in the future.)
libcollectdclient: Add "lcc_identifier_compare".
lcc: network.h: Fix an include.
collectd-tg: Add a first draft of a collectd traffic generator.
libcollectdclient: Add initial network interface.

Still incomplete though.
collectd-tg: Use the networking interface rather than the buffer.
libcollectdclient: Link with libgcrypt if available.
libcollectdclient: Sending signed network packages works now.

Whether the signature is actually correct hasn't been tested yet, though.
libcollectdclient: Implement encryption of network packets.

Warning: Untested code.
collectd-tg: Use the heap to manage the value lists.
collectd-tg: Implemented continuous sending of values.
collectd-tg: Add option parsing and usage information.

It's now possible to configure the parameters on the command line.
collectd-tg: Improve handling of integer command line args.
collectd-tg: Remove the unused "dump_network_buffer" function.
collectd-tg: Improve handling of the interval setting.
collectd-tg: Implement the "-i" argument to specify the interval setting.
Merge branch 'master' into ff/netlib

Conflicts:
	src/collectdctl.c
Merge branch 'master' into ff/netlib
pf plugin: init commit - import pf.c from pyr@openbsd.org