Rdmo

Changes:
* Fix Attribute creation
* Move install_requires to requirements.txt

Steps to upgrade:
* `pip install --upgrade rdmo`
* `python manage.py deploy`

*Please see former release notes to not miss anything when you are updating from a version below 0.14.0.*

Changes:
* Update requirements and remove list_route and detail_route
* Fix project_answers_tree
* Use xelatex with pandoc2

Steps to upgrade:
* `pip install --upgrade rdmo`
* `python manage.py deploy`

*Please see former release notes to not miss anything when you are updating from a version below 0.14.0.*

Changes:
* Fix domain list
* Fix range slider problems concerning Chrome and IE, [issue 137](https://github.com/rdmorganiser/rdmo/issues/137)
* Update dependency library versions
* Merge [pull request 124](https://github.com/rdmorganiser/rdmo/pull/124), fix for Pandoc 2.0 which dropped --reference-odt/docx

Steps to upgrade:
* `pip install --upgrade rdmo`
* `python manage.py collectstatic`
* `python manage.py deploy`

*Please see former release notes to not miss anything when you are updating from a version below 0.14.0.*

This is maintenance release that fixes a bug that occured with a function parameter rename in `djangorestframework`. As described in its [release notes](https://www.django-rest-framework.org/community/release-notes/#390) the url register parameter `base_name` was renamed into `basename`.

From this version RDMO will be using `basename` and be compatible with later `djangorestframework` versions.

By the way:
- Fix a csv utf8 encoding issue

Steps to upgrade:
* `pip install --upgrade rdmo`
* `python manage.py collectstatic`
* `python manage.py deploy`

*Please see former release notes to not miss anything when you are updating from a version below 0.14.0.*

Fixes and new features:
* Switch to Python3, drop Python2 support
* Switch to Django2.2, drop support of older Django versions
* Improve and simplify API

Important to know:
* From version 0.14 on RDMO will not work with Python2 anymore
* With Django 2.1 the support of old MySQL and PostgresSQL versions was dropped. Please look into [Django's release notes](https://docs.djangoproject.com/en/2.2/releases/2.1/#database-backend-api) before you start the RDMO update to make sure your SQL server fits the requirements.

Steps to upgrade:
* `pip install --upgrade rdmo`
* `python manage.py collectistatic`
* Adjust RDMO app's `config/urls.py` to Django2 schemes. The file is much simpler and shorter now. A working example can be found at https://github.com/rdmorganiser/rdmo-app/blob/master/config/urls.py
* note that the entry `MIDDLEWARE_CLASSES` in the `local.py` is now `MIDDLEWARE` only

Fixes and new features:
* Add multi language support
* Add filter to dropdown selections
* Add project csv export
* Add default 'load view_tags' to freshly created view templates
* Fix domain export
* Fix whitespace after view template values

Steps to upgrade:
* python manage.py download_vendor_files
* python manage.py migrate
* python manage.py collectistatic