Add space after comma
Added is_literal, modified literal_symbol
Added tests
Handled AttributeError
Merge pull request #1865 from srjoglekar246/literal

Added is_literal, modified literal_symbol
Merge branch 'master' into 3055-bessel
Added rank() to matrices

Gives the rank of a matrix via rref.
Add Benjamin Fishbein to AUTHORS/aboutus. Welcome to SymPy!
Merge branch 'master' into 3055-bessel
bessel.py: add missing exact values for besseli/j/k/y
bessel.py: eval conjugate() only for (z.is_real and z.is_negative) is False
cleanup test for conjugate()
bessel.py: add generic symmetry in z for besseli/j
bessel.py: more rewrite for besseli/j/y/k
fix rewrite in 746ef01e7b6d0947534ba2 for integer nu