Improve results of Q.algebraic queries

Addressing issue 1077: http://code.google.com/p/sympy/issues/detail?id=1077&q=label%3AeasyToFix&colspec=ID%20Type%20Status%20Priority%20Milestone%20Owner%20Summary%20Stars
E, Pi will now give False with ask(Q.algebraic( ))
GoldenRatio will give True.

Further issues to be resolved: def pow in askAlgebraic is not constrained enough. GoldenRatio**pi is False. Should be None. And few more details.