reduce_data.py:
added --starttime and --endtime arguments (replacing -nt parameter)

filehandlers.py:
 add 'ntimebins' routine that determine 'nt' given a start and end time
 re-ordered the routines alphabetically
missed a space
fixed some typos
fixed up some typos. removed some unnecessary comments
changed start/finish time to match Olaf's sucessful x-corr span
changed output filename to include processing start/end times
started adding psrfits subint data
started adding subint table data saving functionality
Merge branch 'unify_dr' of https://github.com/aberndsen/scintellometry into unify_dr
added more SUBINT table creation functionality... but still more
work to go
done the FITS coding... now need to test
FITS file output is working, though data-integrity need to be verified
FITS output still works. Need to fix lofar functionality, which
is split up

* note, actual data is not verified yet
fixed up FITS overwriting of headers
table data still needs work
filehandlers.py:
    added a new LOFARdata_Pcombined filehandle which takes a list
    of subband files and 'concatenates' them together.
    So this class acts like a single file with lots of subbands
    The code currently doesn't make use of this class.
    I had to introduce a 'seek_record_read' routine to avoid
    lots of seeks since LOFARdata_Pcombined opens lots of files

fold.py:
   * removed 'dtype' argument since this is attached to the filehandle
   * catch exceptions on psrfits processing... this is still a work in
     progress
1) switched LOFAR data-handling to the "combined-subband" mode.
2) ran
time mpirun -np 3 python reduce_data.py -t gmrt -d 2013-07-26 -t0 2013-07-25T22:20:04 -t1 2013-07-25T22:24:04 -nb 10  --nchan 512 -vv
time mpirun -np 3 python reduce_data.py -t lofar -d 2013-07-26 -t0 2013-07-25T22:20:04 -t1 2013-07-25T22:24:04 -nb 10  --nchan 512 -vv
time mpirun -np 3 python reduce_data.py -t aro -d 2013-07-25T18:14:20 -t0 2013-07-25T22:20:04 -t1 2013-07-25T22:24:04 -nb 10  --nchan 512 -vv
scp cita_gw:/cita/h/home-3/berndsen/res/mhvk/scintellometry/scintellometry/trials/vlbi_b1919/*2013-07-25T22:20:04* .
python plot_profiles.py 2013-07-25T22:20:04.000 240

To compare the outputs at UTC 2013-07-25T22:20:04. The GMRT and LOFAR profiles
match up great, but I need to investigate the ARO profile.
fold.py:
    added a 'dedisperse = None' option, which really does *no* dedispersion

observations.conf:
    adjusted observation key timestamps

reduce_data.py:
    switched over lofar processing to LOFARdata_Pcombined,
    which (behind the scenes) concatenates multiple subbands together.
    This makes lofar processing similar to gmrt and aro, since we
    don't have to loop over subband files now
scintellometry/folding/filehandlers.py:
    re-arranged the code
fixes to PSRFITS processing...
still a work in progress
fixed typo on name