Implemented risch_integrate for trigonometric, inverse trigonometric and hyperbolic functions

Earlier
>>risch_integrate(tan(x)+log(x),x)
raised NonImplementedError
Now
>>risch_integrate(tan(x)+log(x),x)
                           ⎛ 2⋅ⅈ⋅x    ⎞
x⋅log(x) + x⋅(-1 + ⅈ) - log⎝ℯ      + 1⎠