initial implementation of sympy.physics.quantum.pauli, containing the pauli sigma operators and states that they act on
made pauli operators commute with boson operators
fix bug in use of warnings module. improved support for normal ordering expression of products of mix of differetnt types of operators
improved support for simplification of products that includes an identity operator
Fixed bug in handling of non-operator base Pow instances in sympy.physics.quantum.operatorordering
support for indices for Pauli operators the in quantum.pauli module
Added allSAT
Added Model class.
Fixed variable naming.
Added returning of False for UNSAT theory.
added function for LaTex printing of Xor statements
keep floor(i) unchanged if i is imaginary symbol
`ufuncify` makes actual ufuncs

This is a rough pass at getting ufuncify to make actual ufuncs. It
works, but needs some cleanup, optimizations, tests, and documentation.
test_numbers: fix minor typo in a test so both >= and <= are tested

The test did `<=` twice.  Use `>=` for one of them.
Merge pull request #7941 from cbm755/fix_test_numbers_typo

test_numbers: fix minor typo in a test so both >= and <= are tested
update fastcache to most recent version in travis tests
Added yielding False for UNSAT theories.
Merge pull request #7946 from pbrady/update_fastcache

update fastcache to most recent version in travis tests
Printing: print x**-1.0 differently from 1/x

`x**-1.0` and `x**-1` should print differently.  Fixed this and added
tests.  Pretty printing seemed to work already but tests added.
Close #2860 which is related (it seems fixed but added tests).
Changed __add__ to return the correct phase for the addition of two TWave objects