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
Enhancements of the sin function
Enhancements of the cos function
Enhancements of the tan function
Enhancements of the cot function
Enhancements of the csc function
Enhancements of the sec function
Implementing common base class for inverse trigonometric functions
Enhancements of the asin function
Enhancements of the acos function
Enhancements of the atan function
Enhancements of the acot function
First implementation of the asec function
First implementation of the acsc function
Enhancements of the atan2 function
Reduce code duplication in as_real_imag of trigonometric functions
fix cot fdiff