Processpiper

* Fixed [56](https://github.com/csgoh/processpiper/issues/56): Thanks to [Charizhardt](https://github.com/Charizhardt), the following elements are added to the incoming and outgoing nodes
* startEvent, endEvent, intermediateCatchEvent, task, subProcess, serviceTask, exclusiveGateway, inclusiveGateway and parallelGateway

New Feature:
- Export diagram to .bpmn (XML) format. See this [page](https://github.com/csgoh/processpiper/wiki/How-To#how-to-export-diagram-to-bpmn) for more information.

* `text2diagram.render()` function enhancements. See this [page](https://github.com/csgoh/processpiper/wiki/Usage-Documentation) for more information.
* You can now display the generated code by setting `show_code=True`.
* Added 'SVG' output option. Addressing feature request [43](https://github.com/csgoh/processpiper/issues/43).
* Updated font size and spacing between elements
* You can now change font size for title, element and footer. See this [page](https://github.com/csgoh/processpiper/wiki/How-To#how-to-change_font_size) for more information.

* Simplified connection implementation and fixed issues where some diagrams cannot be rendered.
* Added the ability to configure connection direction manually. See this [page](https://github.com/csgoh/processpiper/wiki/How-To#how-to-select_sides) for more details.
* Added new validation. All shapes (except start, end and others events) require an incoming connection.
* Added five additional colour schemes. Visit [Gallery](https://github.com/csgoh/processpiper/wiki/Gallery) to see the colour schemes.
* :heavy_exclamation_mark: There is a breaking change made to processpiper.text2diagram package. See this [Breaking Changes](https://github.com/csgoh/processpiper/wiki/Breaking-Changes) for further information.

* Implemented SVG painter [14](https://github.com/csgoh/processpiper/discussions/14). You can now save your diagram in SVG file format. See [Wiki](https://github.com/csgoh/processpiper/wiki/Usage-Documentation) for more details.
* Implemented maximum connections validation [31](https://github.com/csgoh/processpiper/discussions/31). i.e. An element can have up to a maximum of 4 connections (incoming and outgoing connection combined).

* Fixed layout and connections issue

v.0.4.2