added and modified doc strings.  removed unused functions from geometry.py
trivial change
added some functions and worked on isolation crit
working on isolation criterion.  changed inside_volume to also return a list of arrays of points inside each volume
added match function to utils
worked on HOD and isolation crit.  neither works yet, as mock.galaxies needs more functionality.
Merge pull request #10 from duncandc/develop

Develop
Merged Duncan's Pull Request #10

ream/develop' into develop

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