Rip out Channel Access Server code

Replace the 'pcaspy' library with the 'pyepics' library.  Pyepics
doesn't do the server part, though, so that has to be handled by an
external softIOC program.  (Which is fine, because it looks very much
like pcaspy didn't do the server thing very well.)

This is the first step.  It's writing to the process variables (which is
the main thing), but the softIOC needs to be started mannually.  There's
some work to be done to make that step easier to automate.
Generate config files for softIoc

Added code to generate the necessary config files for the softIoc binary
from the settings in the config file.  Also added a command line option
to call this code and then exit.
Add PyEpics library

Since RHEL6 doesn't seem to have an rpm for the pyepics library, I'm
adding its source code directly to the repo.  Hopefully, this is a
temporary thing until we can get a pyepics rpm for RHEL6
Update startup scripts to use the softIoc binary

Added a script in bin to start the python with the proper command line
to auto generate the softIoc config files.  Also modified the existing
startup script to modify PYTHONPATH so that it can find the local epics
code.  Modified the initd template to generate the softIoc commands,
start softIoc and then start the main python code.  Also added code to
shut everything down properly.  Last, modified setyup.py to include all
the new files in the RPM.
Change search order for Mantid libraries

When updating sys.path() with the Mantid library directory, don't do an
append; do an insert before position 0.  (This way, we're sure that the
Mantid library that is found is the one we want not a different version
that happened to be somewhere else in the search list.)
Add event histogram plugin

First cut at a plugin to output event histograms.  Including a quick
python script to read the PV data and display an image.  Compared to what I
see in the MantidPlot instrument view, the data looks correct.  Need a
more precise test, though.

Note:  Since this is a waveform PV, the .db file generated by the
--generate_softioc_files command line option will be wrong!  It needs to
be modified by hand.  (Yes, this is something I intend to fix very
soon!)
Minor change to PV database records

Add the SCAN field to the records in the .db file.
Minor change to initd template file

Use the daemon function to start the procserv executable
Changes to default config file

Change which PV's are configured in the default config file.