Addition of hypertangent and exponential cases to parametric differntial equations

 added code exponential for to special denom

added code for tangent cases to special denom

added code for tangent cases to special denom

First attempt to solve the section 5.12

first attempt to solve section 5.12 and related problems

First Attempt to implement section 5.12 and related problems

added hypertangent test cases for param special

deleted binary file
as_real_image not working as expected
real_img function in prde.py

This commit enables us to evaluate real and imaginary parts of multivariate polynomials
Given numerator and denom of a function and the generator, it converts the poly into a dict with the degree of DE.t as the key
and the cofficients(corresponding to the degree of the variable) as the value. Inturn it seperates
the degrees with respect to mod 4
added code exponential for to special denom

added code for tangent cases to special denom

added code for tangent cases to special denom

First attempt to solve the section 5.12

first attempt to solve section 5.12 and related problems

First Attempt to implement section 5.12 and related problems

added hypertangent test cases for param special

Also solves the previous issues:
-> General code cleanup
(spaces after commas, spaces around operators, more even line wrapping in the docstring).
-> Seperates the real and imaginary parts to prevent param_log_deriv_heu faliure
(Avoids faliure due to complex extenions by using real amd imag parts seperately)
-> All unification error are avoided
(A major problem in previously failed commits)
->Add doc string to real_img
(Puts a description to the real_imag function in prde.py)
This PR solves the following:

 -> Avoids unneccesary coversions of polynomials to expressions
    which eliminates the cause of most of the unification errors
 -> Adds more tests to recognize_derivative in risch.py
Merge pull request #2049 from cheatiiit/special

Addition of hypertangent and exponential cases to Partial Differntial Equations