Forte Release v0.3.0.dev3

• Build and implement the Payload system: #828, #892, #896
• Improve Computer Vision integration: #879, #877, #876, #891, #893
• Data-efficiency improvement: #849, #882, #886, #899
• Improve documentation and tutorials: #854, #846, #889, #897
• Several clean up and bug fixes: #852, #854, #861, #870, #872,
• This is a pre-release version and some features are still in development. The recommended version right now is forte==0.2.0.