Change make_healpixdb.py to work with eg. opsim DB
Change make_healpixdb.py to work with eg. opsim DB

- Modify the script/make_healpix.py to work with
  opsimsummary/example_data/enigma_1189_micro.db by using sqlalchemy to
  read in the WFD fields through a sql query and changing the input file
  name
- Modify NSIDE to 1 from 256 to speed things up
- Modify the name of the output sqlite database to reflect that the
  micro database has been used.
- Note that due to these modifications the output database is ~ 4 MB
  rather than the ~ 20 GB database for ENIGMA or MINION
- The ipix, and obsHistID columns have been interchanged

	modified:   scripts/make_healpixdb.py

rbiswas4/simlib