Transifex-client

* Push and pull files more quickly by using the new `--parallel` option
with `tx push` and `tx pull` to make parallel requests. This is a beta
feature - be careful when using it with many files as it may cause you
to hit your API rate limits.

* `--expression` is now a named argument for `tx config mapping` so it’s
consistent with the `tx config mapping-bulk` command with regard to
how you pass a file path expression.

* The algorithm for locating translation files has been optimized to
improve performance in cases where you have many files in your working
directory.

* Fix some python 3 compatibility issues
* Fix CI for python 3
* Add Python 3.6 in the supported versions

_Note: For windows executables for more python version see: https://ci.appveyor.com/project/transifex/transifex-client/build/1.0.445._

* Rename set command to `config` while maintaining backwards compatibility.
* `--auto-local`, `--auto-remote` options have become `mapping` and `mapping-remote` subcommands. Backwards compatibility has been maintained and the options (and subcommands) are supported both when using `tx set` and `tx config` commands.
* Introduce `mapping-bulk` subcommand to `tx config` command. `mapping-bulk` is similar to `mapping` but configures a whole directory of files and not a single file.
* Support branch specific push / pull using the `--branch` option.
* Add interactive wizard for `tx config` command. Interactive wizard is triggered by default after `tx init` if `--skipsetup` option is not passed and by the `tx config` if called without any options or subcommands.

Changelog

* Support for Basic Authentication when using the client behind a proxy
* Support for `sourceastranslation` and `onlyreviewed` modes when pulling files
* Return non-zero exit codes on errors
* `$ tx --version` now includes information about the Python version and architecture you’re running
* Some updates and minor fixes in logging/error messages