akleeman/xray — pull request #107 by shoyer (2014-04-27 23:00:18+00:00)
Title: Deprecated 'attributes' in favor of 'attrs'

Also:
1. Don't try to preserve attributes under mathematical operations.
2. Finish up some cleanup related to "equals" and "identical" for testing.
3. Options for how strictly to compare varaibles when merging or concatenating
(see #25).

Fixes #103 and #104.