Sign Error in Unrad Function issue #8622

Added Test for SIgn Error in unrad

	assert unrad((root(x + 1, 5) - root(x, 3))) == (x**5 - x**3 - 3*x**2 - 3*x - 1, [], [])

Added Test for SIgn Error in unrad issue #8622

Added Test for issue #8622
assert unrad((root(x + 1, 5) - root(x, 3))) == (x**5 - x**3 - 3*x**2 - 3*x - 1, [], [])
Fix Pow._eval_is_integer in case base.is_integer is False

closes #8641
Changed solve to work for non-linear piecewise functions

Changed solve to fix #8587 and added a test.
Merge pull request #8645 from skirpichev/8641-fix

Fix Pow._eval_is_integer in case base.is_integer is False
Merge pull request #8680 from nishithshah2211/issue8587

Bug fix #8587
Merge pull request #8647 from aktech/master

Fix sign Error in Unrad Function issue #8622 …
Fixes issue8666 solvers
Add AMiT Kumar to AUTHORS/aboutus. Welcome to SymPy!
Parial fix for issue #8677: exclude early exit in equals() for Mod
Add Nishith Shah to AUTHORS/aboutus. Welcome to SymPy!
Merge pull request #8687 from skirpichev/8677-fix1

Parial fix for issue #8677: exclude early exit in equals() for Mod
Merge pull request #8686 from smichr/auth

Auth
both lhs and rhs should be checked in solve
Add _eval_is_algebraic helpers for re/im/conjugate/abs

fixes #8656
Merge pull request #8684 from aktech/issue8666

Solve returns correct solution for Equations where denominator becomes 0 (fixes #8666)
Rewrite Gamma as Factorial #8621

Code quality improved for pull 8700
Merge pull request #8700 from aktech/issue#8621

Function to Rewrite Gamma as Factorial #8621
Merge pull request #8699 from skirpichev/8656-fix

Add _eval_is_algebraic helpers for re/im/conjugate/abs
Add is_real functionality for factorial fix 8658
Merge pull request #8706 from aktech/issue8658

Add is_real functionality for factorial, Fix issue #8658