shut of trigsimp when using fu

simplify in TR0 calls trigsimp; if fu is being used then calls
to trigsimp if there are trig functions are shut off.  This is
not the best thing (since if there is a single hyperbolic in the
expression, the call to trigsimp will still be made).

Also, I'm not sure what best simplifications are needed in TR0;
the original paper should be consulted.

These are some expressions that aren't simplified as they might
be in the Fu:

    def trigsimp(e, **kw):
        return fu(e)
    a, x, y = symbols('a x y')
    assert trigsimp(diff(integrate(cos(x)/sin(x)**7, x), x)) == \
           cos(x)/sin(x)**7
    assert trigsimp(sin(2)*sin(3) + cos(2)*cos(3) + cos(2)) == cos(1) + cos(2)
    eq = cos(2)*(cos(3) + 1)**2/(cos(3) - 1)**2
    # use exclusion
    assert trigsimp(eq) == eq
    # but not unnecessarily
    assert trigsimp(cos(2)*(cos(3) + 1)**2*(cos(3) - 1)**2) == \
        cos(2)*sin(3)**4
    assert trigsimp(1/sin(x)**2 - 1) == \
        cot(x)**2 \
        # not tan(x)**-2
    assert trigsimp(tanh(x + y) - tanh(x)/(1 + tanh(x)*tanh(y))) == \
        tanh(y)/(tanh(x)*tanh(y) + 1) \
        # not tanh(y)*tanh(x + y)/(tanh(x) + tanh(y))
    assert trigsimp(tan(2)**2*cos(3)*exp(2)*cos(2)**2) == \
        sin(2)**2*cos(3)*exp(2) \
        # not 4*exp(2)*sin(1)**2*cos(1)**2*cos(3)
    assert trigsimp(cot(2)*cos(3)*exp(2)*sin(2)) == \
        cos(3)*exp(2)*cos(2) \
        # not exp(2)*cos(1)**2*cos(3) - exp(2)*sin(1)**2*cos(3)
    assert trigsimp(tan(2)*cos(3)*exp(2)/sin(2)) == \
        cos(3)*exp(2)/cos(2) \
        # not exp(2)*cos(3)/(-sin(1)**2 + cos(1)**2)
    assert trigsimp(cot(2)*cos(3)*exp(2)/cos(2)) == \
        cos(3)*exp(2)/sin(2) \
        # not exp(2)*cos(3)/(2*sin(1)*cos(1))

Note that the last expression passes if the numbers are replaced with
symbols, so it could be that one of the simplification functions in
TR0 is to blame -- I am not aware of any special bias against numbers
in the other simplification routines.