Codestyle updates, more compatibility and secutiry

In this release I'm introducing more compatibility towards older third party libraries (adding compatible versions) and updating the code style, though there should be not BC breaking changes :)

Also I added a number of files that should help to clean this repository (and its code) clean, for example the .editorconfig file, GrumPHP, Psalm and PHP-CS-Fixer.

Changes

• Switching PHP requirement to ^7.1
• Changing compatible Guzzle versions from ^6.5|^7.0 to ^5.3|^6.2|^7.0
• Changing compatible JSON Mapper versions from ^1.6|^2.0 to ^2.0|^3.0|^4.0
• Adding friendsofphp/php-cs-fixer (+ configuration)
• Adding psalm/phar (+ configuration)
• Adding phpro/grumphp-shim (+ configuration)
• A lot of Code style changes (NO functional changes)

Updating guzzlehttp/guzzle dependency

Here's an update regarding the dependencies!

Changes

• Updated guzzlehttp/guzzle to ^6.5|^7.0

Updating dependencies, removing 'pre-release'

Here's an update regarding the dependencies!

Changes

• Updated netresearch/jsonmapper to either ^1.6 or ^2.0
• Updated guzzlehttp/guzzle
• Removed the 'pre-release' flag, but please note there are still a lot of missing methods

DataTypes and new UserService and WorkspaceService method

Here's a new release with a few improvements, cleaned up code and breaking changes (the *Item classes have been moved to another namespace).

There is still a lot of work left... And possibly some breaking changes :/

Changes

• Data types (like 'Workspaces', 'Lists', 'Elements' and so on) now extend AbstractDataType which makes life a little easier :)
• EntryCollection->entries is now called EntryCollection->listEntries as in the raw API response

New methods

API

• Convenience method getUserService

Users

• getCurrentUser

Workspaces

• getUsersForWorkspaces

First release: v0.1 (beta)

This first release marks a working "base" API client that does ship with the following services and API methods:

elements

• addElementToList
• getElementsInList
• reorderKanban
• updateElementInList

entries

• getEntry
• getEntriesForListView
• getEntriesFromFilter

lists

• getList
• getListsWithoutWorkspaceAccess

workspaces

• getWorkspace
• getAllWorkspacesAndLists

Currently we are planning to implement most of the API endpoints via according service classes and methods, so there's a lot more to come (including breaking changes ;) ),