InputCatalog items are safe to reuse if component items are safe.  (e.g. if index is a constant, rather than a Sequence)
(#449)
Improve optimization flags we use for g++
(#449)
Use explicit SSE code for time-critical part of KTable.interpolate
(#449)
Store invdk, invN, etc. at class level so don't have to recalculate each time.
(#449)
Merge branch '#439' into #449
Don't add components to an Add object if flux=0
(#449)
more micro-optimizations in interpolate
(#449)
Add DictFile class as a way to read in a dict from pickle, yaml or json file
(#449)
Allow input fields to be lists
(#449)
Unit tests for new DictFile and list features
(#449)
Fix error in power_spectrum initialization with the new list format
(#449)
Rename InputCatalog -> Catalog and DictFile -> Dict
(#449)
Enable multi-key arguments to Dict
(#449)
Add offset option for all image types
(#449)
Merge branch 'master' into #449

Conflicts:
	galsim/optics.py
Merge branch '#442' into #449
Only make Add or Convolve if there is more than 1 item
(#449)
Fix Tiled behavior when index_convention=0
(#449)
Allow more flexible options for dict extensions
(#449)
Merge branch '#325' into #449