Added doctests for slope and deflection.
Added doctests for slope and deflection.

sampadsaha5/sympy,souravsingh/sympy,kaushik94/sympy,skidzo/sympy,madan96/sympy,kaushik94/sympy,postvakje/sympy,madan96/sympy,souravsingh/sympy,chaffra/sympy,yashsharan/sympy,kaushik94/sympy,chaffra/sympy,aktech/sympy,postvakje/sympy,madan96/sympy,yashsharan/sympy,sampadsaha5/sympy,yashsharan/sympy,jaimahajan1997/sympy,chaffra/sympy,jaimahajan1997/sympy,skidzo/sympy,aktech/sympy,souravsingh/sympy,postvakje/sympy,aktech/sympy,skidzo/sympy,sampadsaha5/sympy,jaimahajan1997/sympy