3083: Not now accepts only one argument
solve: return all independent solutions.

Now solve will return all independent solutions instead of breaking
out at the first solution found.
3083_not:Changes
3083_not:changed args to arg
3083_not: Rectified a mistake of previous commit- arg.arg changed to arg.args
I hope it is correct now.
solve: Return all independent solutions (underdetermined systems).
solve: handle Matrix equations.

If we have a Matrix equation Eq(A*B, C), it is transformed into a
system [A*B - C]. We need to iterate over the elements of the matrix
A*B - C again, turning the Matrix equation into a system of equations.

Fixes issue 771: Matrix equations
http://code.google.com/p/sympy/issues/detail?id=771
Incorrect Exception in dsolve()
added tests
added tests
solve: Test multiple matrix equations.
Extened the named groups module to include information about

whether or not the naemd groups are nilpotent or solvable.
extended_named_groups : some corrections.
Merge pull request #1810 from meclark256/extended_named_groups

Extended the named groups module to include information about nilpotency and solvability
Add Mary Clark to the AUTHORS/aboutus. Welcome to SymPy!
Merge pull request #1783 from rishabh-git/3083_not

Issue3083: Not accepts only one argument
Add Rishabh Dixit to the AUTHORS/aboutus. Welcome to SymPy!
Merge pull request #1803 from Manoj-Kumar-S/1996_issue

Incorrect Exception in dsolve() : First implementation
Add Manoj Kumar to the AUTHORS/aboutus/.mailmap. Welcome to SymPy!
Merge pull request #1802 from jrioux/matrices

solve: handle Matrix equations.