Description 
Example: simplify the system of equations
{x^2+2xy^2=0, xy+2y^3=1}
>> groebner({'x^2+2*x*y^2','x*y+2*y^31'},'lex',{'x','y'})
returns {'y^30.5','x'}
Solve equations:
>> polynsolve({'x^2+2*x*y^2','x*y+2*y^31'},'',{'x','y'})
returns [0, 0.3969 + 0.6874i; 0, 0.3969  0.6874i; 0, 0.7937]
>> polynsolve({'x^2x','x*y1'},'',{'x','y'})
returns [1, 1]
>> polynsolve({'x^2x','x*y'},'',{'x','y'})
returns [0, NaN; 1, 0]
(infinite possibilities represented by NaN)
NOTE: calculation of Groebner bases in floatingpoint arithmetic can be numerically unstable. See the help text for more details.
