SymPy 1.2 release candidate 1

[Aaron Meurer]

I'm happy to announce that the first release candidate for the 1.2
release is ready for testing. Please download it from
https://github.com/sympy/sympy/releases/tag/sympy-1.2rc1 test it. I
plan to do the final release by the end of this week.

The release notes for this release are at
https://github.com/sympy/sympy/wiki/Release-Notes-for-1.2. I am still
working on compiling these, but if you know of any missing changes, or
changes that should be listed as highlights, feel free to edit that
page.

Some highlights for this release are:

* Python 3.3 is no longer supported. If you require Python 3.3 support, use
SymPy 1.1.1. See our
[policy](https://github.com/sympy/sympy/wiki/Python-version-support-policy)
on dropping support for major Python versions.

* Experimental LaTeX parsing with `sympy.parsing.latex.parse_latex()` has been
added, based on the `latex2sympy` project. This requires
`antlr-python-runtime` to be installed.
[#13706](https://github.com/sympy/sympy/pull/13706)

* The vector module has been improved to support orthogonal curvilinear
coordinate systems ([Szymon Mieszczak's GSoC
project](https://github.com/sympy/sympy/wiki/Szymon-Mieszczak,-GSoC-2017-Report,-Implementation-of-multiple-types-of-coordinate-systems-for-vectors))

* New module sympy.integrals.intpoly for integrating uni/bivariate polynomials
over 2-polytopes. ([Arif Ahmed's GSoC
project](https://github.com/sympy/sympy/wiki/GSoC-2017-Report-Arif-Ahmed-:-Integration-over-Polytopes))

* Improvements to the code generation module. ([Björn Dahlgren's GSoC
project](https://github.com/sympy/sympy/wiki/GSoC-2017-Report-Bj%C3%B6rn-Dahlgren:-Improved-code-generation-facilities))

* Improvements to the group theory module. See below for more information.
([Valeriia Gladkova's GSoC
project](https://github.com/sympy/sympy/wiki/GSoC-2017-Report-Valeriia-Gladkova:-Group-Theory))

Other GSoC projects, [Abdullah Javed
Nesar](https://github.com/sympy/sympy/wiki/GSoC-2017-Report-Abdullah-Javed-Nesar:-Rule-based-Integrator),
[Arif
Ahmed](https://github.com/sympy/sympy/wiki/GSoC-2017-Report-Arif-Ahmed-:-Integration-over-Polytopes),
and [Gaurav Dhingra](https://github.com/gxyd/GSoC-2017-Report) are work in
progress improvements to the `integrate` module (particularly, the new `rubi`
submodule and the `risch` submodule), which are not yet visible to user-facing
code.

See the release notes for the full list of changes.

Aaron Meurer