fixes factor(), separatevars(), combsimp() from Issue #6280
Update ask.py

TautologicalHandler is in _val_template + "common" + TautologicalHandler
Show that init_session() runs init_printing()
polyroots: always refine all roots

Previously if the given root was already converged, it wasn't refined. But this
seems to increase the number of iterations needed to converge considerably.
polyroots: Raise error if convergence not achieved
polyroots: chop small numbers in "cleanup" mode

Previously only small real or imaginary parts were chopped. But if abs(x) is
close to zero, we want to chop this case as well.
polyroots: use `extraprec` argument

Previously this argument was not used at all by a mistake and instead the
default value 10 was assigned directly.
polyroots: fix tolerance calculation

We now set the tolerance `tol` directly equal to `ctx.eps`. This is the right
way to do it, since if more working precision is needed, the user needs to
assign the `extraprec` argument.
Refactor nroots() to make it more robust

The following changes were made:

* The polynomial coefficients are always converted to integers. Previously, a
  floating point number was used instead, which loses accuracy, and then for
  higher order polynomials (e.g. Legendre of order 64) one has to use large
  working precision just to represent polynomial coefficients accurately
  enough (otherwise one gets inaccurate roots, for example complex roots
  solution instead of real ones). Now this problem is completely avoided.

* We set extra precision in polyroots() based on the polynomial order.
  "10*order" seem to work well. This formula can be adjusted. This takes care
  of the problem that higher order polynomials suffer from numerical
  cancellation.

* We remove the `error` argument. Now the error is always either lower than `n`
  digits, or an exception is raised.

* The roots are now ordered by mpmath, which returns the correct ordering (real
  roots first, then complex ones).
Add tests for nroots()

We test roots of Legendre polynomial of order 64, as well as some smaller
polynomials. Besides accuracy, these tests also ensure the proper ordering of
the roots.
polyroots: use NoConvergence instead of Exception

A test written as well.
Add a note to tests about the roots order
ODE:Corrected classify_ode of separable_reduced Issue #6950

There were few equations like sin(x)*cos(f(x)) + cos(x)*sin(f(x))*f(x).diff(x) which separable_reduced classified but was not able to solve because it was not fitting in its general form. So, this patch modifies classify_ode of separable_reduced so as not to classify those equations which are out of its scope.
plot_implicit and legend

The return value of self.ax.legend() should be checked first and then
the call to set_visible() be made.
Merge branch 'master' of git://github.com/sympy/sympy
Merge pull request #7400 from amitsaha/plot_implicit

plot_implicit and legend
new assumptions for inverse trig functions
fixes pyglet doctest problems

fixes TypeError and KeyError exceptions in the pygletplot package

    Traceback (most recent call last):
      File "/usr/lib64/python2.7/doctest.py", line 1289, in __run
        compileflags, 1) in test.globs
      File "<doctest sympy.plotting.pygletplot.__init__.PygletPlot[29]>", line 1, in <module>
        p[2] = -x**2-y**2
      File "sympy/plotting/pygletplot/plot.py", line 320, in __setitem__
        f = PlotMode(*args, **kwargs)
      File "sympy/plotting/pygletplot/plot_mode_base.py", line 164, in __init__
        self.style = self.options.pop('style', '')
      File "sympy/plotting/pygletplot/plot_mode_base.py", line 174, in w
        r = f(self, *args, **kwargs)
      File "sympy/plotting/pygletplot/plot_mode_base.py", line 327, in _set_style
        v = ['both', 'solid'][step_max > 40]
    TypeError: list indices must be integers, not BooleanFalse

    Traceback (most recent call last):
      File "/usr/lib64/python2.7/doctest.py", line 1289, in __run
        compileflags, 1) in test.globs
      File "<doctest sympy.plotting.pygletplot.__init__.PygletPlot[30]>", line 1, in <module>
        p[2].style = 'wireframe'
      File "sympy/plotting/pygletplot/plot.py", line 301, in __getitem__
        return self._functions[i]
    KeyError: 2

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
remove redundant condtion

We already know that radicals is True since the preceding line
returned if `not radicals` was True.
old assumptions for inverse trig functions
A minor change in tests for new assumptions