for numpy 1.6
removed all superfluous operations from GMOSPrepare. Moving on to CutSlits
Merge pull request #24 from mhvk/older-numpy

for numpy 1.6
fixed the GMOSPrepare and split off the slit cutting
added chip gap information
finished preliminary implementation of mask cutting
Merge branch 'master' into gmos/split_up_slit_cutting

Conflicts:
	geminiutil/gmos/gmos_basics.py
Merge pull request #25 from wkerzendorf/gmos/split_up_slit_cutting

Gmos/split up slit cutting
Keep Prepare class in gmos_prepare, PEP8 clean-up of gmos_basics
Merge pull request #26 from mhvk/gmos/keep-prepare

Keep Prepare class in gmos_prepare, PEP8 clean-up of gmos_basics
updated calculation for slice positions
in the middle of updating the slice cross correlator. switching now to get science frames associated with their calibration data.
Basic procedures required for wavelength calibration, esp of day-time arcs
changed date-obs to mjd using astropy time
added the possibility of using the .science_query option to get the query object back
1/0 in there.  building the flat, arcs, ... finder.
fixed the instrument_setup from_fits_file classmethod. it was returning not the same instrument_setup even if it did exist already.
added mask_arc and flat_id
finalized the science frames
added the slices to the science_frame