Modified latex printing of Lambda to use \mapsto
Modified tests so working with \mapsto version of Lambda
Removed  that I forgot about in test_latex.py
Modified tests to include parentheses around whole Lambda expression
Corrected tests for Lambda
Add medium [skip ci]
Add feature to initialize medium with refractive index. [skip ci]
Import constants like permittivity of free space, speed of light in vacuum and magnetic permeability from sympy.physics.units rather than using Symbols for them.
Add tests for medium
Add args test for Medium
Add note for the commented failing test
Generate doc/man/isympy.1 from the isympy.xml source
Remove unnecessary flag and change default params
method for linear system of 3 or more eq of 1st order
Methods of linear system of 3eq and 1st order
Added linear system of n equation of 1st order
Added test cases
Made changes in linear system of 3eq 1st order type4
method for linear system of 3 or more eq of 1st order
Methods of linear system of 3eq and 1st order
Changed eigen_vector