* Set VIRTUAL_ENV enviroment in activate_this.py

VIRTUAL_ENV was not set in activate_this.py, while set in other activate scripts.

* Add tests for activate_this.py

* Fix syntax in test_activate_this.py

* fix

* more robust testing for the activate this

* fix Jython support of activate this

- global variables capital
- pep-8 compliant variable names
- some pycharm specific ignores
- fixed some typos
- prefer format over %

* Always store _OLD_VIRTUAL_PATH in a sh compat format

When using a subshell from fish while within a virtualenv the
_OLD_VIRTUAL_PATH variable ends up in fish format and not the format of
the subshell. This breaks the first step of the activate script where it
attepts to deactivate the previous environment.

This patch will handle conversion to and from sh and fish formats within
the activate.fish script

* Add test and update to new delimiter

* Fix lint

Remove line that didn't lint as we don't need it.

* Rebuild virtualenv.py

* Add changelog

* fix_lint

* Try to add fish to build env

* Use less fish (only when running py tests)

* remove code duplication for activation testers

* Consolidate activation testing

- add tests for csh, bash
- rework bash, csh tests
- remove powershell singing
- powershell pydoc support

* file and with extension

* universal newline

* Add debug env var, and normalize on Linux to via realpath (Jython failure)

* switch to bat

* fix xonosh

* fix xonsh further

* fix jython

* fix lint

* enable pytest debug

copyfile was broken for symlinks that pointed to relative paths, and for
symlinks that pointed to further symlinks (which meant that virtualenv
failed to work in some cases when the Python executable it found was
a symlink, e.g. when Python had been installed using stow or homebrew;
issue #268).

Make it follow symlinks until it finds an actual file to copy.

- added docs on running the internal test suite using `tox`
- added a test for creating a Python environment in a path with spaces
- added a test for creating a Python environment while locating the needed wheel sources in a path with spaces

See https://github.com/pypa/pip/blob/master/src/pip/_vendor/README.rst

It is acceptable to remove the pip/_vendor/requests/cacert.pem file from pip

Virtualenv should not error on that

fixes #1248

* initial version of xonsh activate

* partially add activate.xsh to virtualenv.py

* Add base64-encoded xonsh script

* actiavte.xsh

* some initial tests

* fixed deactivate argument error

* added source command to xonsh test and added newline to the end of activate.xsh

* remove powershell refs

* add xonsh to testing requirements

* black tests/activation/test_xonsh_activation.py

* need raw string to escape paths in windows

* some path safety fixes

* put in some debug for tests

* black the test

* change import order

* added docs

* @gaborbernat feedback

* better python version constratints for xonsh

* black

* xonsh install version includes minor

* refactor need_xonsh

* removed unused import

* removed blank line

* Added activate.ps1 to list of generated activation scripts
* extended tests to cover cmdline
* Use path_locations to test directories
* Add tests for powershell activation
* Fix environment creation for cmdline tests
* pwsh.exe on Windows
* make executable dependent tests optional locally
* fixes
* fix path normalization and casing
* turn path to long
* debug
* fix documentation