Stability improvements

[josesimoes]

Description

• Remove call to Start in ConnectAsync because we need to have better control over this
• Add code to check for invalid Capabilities on ConnectAsync and failing on error
• Made Engine.Start return Task so it can be properly used as a Task
• Improve cancellation token management in Engine.Start
• Rework code to add devices to nanoDevices collection
• Rework code to ReadBufferAsync in order to prevent throwing exceptions on errors
• Update WPF test app

Motivation and Context

• Addresses stability issues
• Helps resolving VS is restarting when trying to connect/reconnect to device Home#247

How Has This Been Tested?

Screenshots

Types of changes

• Improvement (non-breaking change that improves a feature, code or algorithm)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Signed-off-by: José Simões jose.simoes@eclo.solutions

[nfbot]

Hi @josesimoes,

I'm nanoFramework bot.
Thank you for your contribution!

A human will be reviewing it shortly. 😉