runtime transport changes

[Martin Hunt]

I've checked in the following changes to stpd and the runtime transport.

1. Netlink is conpletely removed. It has been replaced with a
filesystem-based transport that lives in /proc/systemtap.  This is now
the default.

2. To use relayfs, you define STP_RELAYFS.  See shellsnoop.c for an
example.

3. stp-control.ko is gone.

4. The "stp" scripts are gone.  Just run "stpd modulename".  stpd will
attempt to find a script named "stp_check" to compile and load the
relayfs module if it isn't already loaded.  The rpm puts stp_check
in /usr/libexec/systemtap, but if you are running a stpd that wasn't
built as part of an rpm, it won't know to look there.  Copy it (or link
to it) to your path somewhere. The relayfs module will currently get
loaded even if it is never used.

5. Relayfs doesn't work on rawhide kernels, but the new transport works
fine.

Please let me know if you find any problems.  

Martin