[Halld-offline] HDEVIO beta testing

[David Lawrence]

Hi Offliners,

  I have checked in some changes to the DAQ plugin that implement an alternative for reading in the EVIO
files. This addresses some of the corruption issues we’ve been seeing, particularly with data taken after
the Thanksgiving break. The new code implements error recovery so that it can skip past bad areas it
detects within the file. It also allows use to reallocate user buffers if it runs across a large event (this
was the problem forcing to allocate 20MB buffers.)

  Testing of this has been *extremely* limited up to now so it is still not the default. Early adopters who want
to help with beta testing can enable it by setting  the #define of USE_HDEVIO at the top of the 
DAQ/JEventSource_EVIO.cc file to 1 instead of zero and recompiling.

For those brave souls willing to test this out, please send me any feedback. Particularly if you
come across a file that causes a crash.

Regards,
-David