Dynet

Pandoc was causing the pypi wheel to fail to compile, this release fixes that issue.

Some small fixes, including Python 3.8 support.

DyNet v. 2.1 incorporates the following changes:

* __Parameters are now implicitly cast Expressions in python.__ This changes the API slightly as there is no need to call `dy.parameter` or `.expr` anymore. 1233
* Python 3.7 support (pre-built binaries on PyPI) 1450 (thanks danielhers )
* Advanced Numpy-like slicing 1363 (thanks msperber)
* Argmax and straight-through estimators 1208
* Updated API doc 1312 (thanks zhechenyan)
* Fix segmentation fault in RNNs https://github.com/clab/dynet/issues/1371
* Many other small fixes and QoL improvements (see [the full list of merged PRs since the last release](https://github.com/clab/dynet/pulls?utf8=%E2%9C%93&q=is%3Apr+is%3Amerged+merged%3A%3E%3D2018-02-16+) for more details)

Link to the 2.1 documentation: https://dynet.readthedocs.io/en/2.1/

DyNet v. 2.0.3 incorporates the following changes:

* On-GPU random number generation (https://github.com/clab/dynet/issues/1059 https://github.com/clab/dynet/pull/1094 https://github.com/clab/dynet/pull/1154)
* Memory savings through in-place operations (https://github.com/clab/dynet/pull/1103)
* More efficient inputTensor that doesn't switch memory layout (https://github.com/clab/dynet/issues/1143)
* More stable sigmoid (https://github.com/clab/dynet/pull/1200)
* Fix bug in weight decay (https://github.com/clab/dynet/issues/1201)
* Many other fixes, etc.

Link to the documentation: [Dynet v2.0.3](http://dynet.readthedocs.io/en/2.0.3/)

v 2.0.2 of DyNet includes the following improvements. Thanks to everyone who made them happen!

Done:

Better organized examples: https://github.com/clab/dynet/issues/191
Full multi-device support: https://github.com/clab/dynet/issues/952
Broadcasting standard elementwise operations: https://github.com/clab/dynet/pull/776
Some refactoring: https://github.com/clab/dynet/issues/522
Better profiling: https://github.com/clab/dynet/pull/1088
Fix performance regression on autobatching: https://github.com/clab/dynet/issues/974
Pre-compiled pip binaries
A bunch of other small functionality additions and bug fixes

Simplified training interface: https://github.com/clab/dynet/pull/695
Support for multi-device computation (thanks xunzhang !): https://github.com/clab/dynet/pull/704
A memory efficient version of LSTMBuilder (thanks msperber): https://github.com/clab/dynet/pull/729
Scratch memory for better memory efficiency (thanks zhisbug Abasyoni !): https://github.com/clab/dynet/pull/692
Work towards pre-compiled pip files (thanks danielhers !)