Updates dependencies, adds license information to NuGet package and updates README.md

Update to BotBuilder 4.5.1 to resolve:

Merge pull request #38 from tompaana/development

Bumps the version number to 2.0.2-alpha.

Merge pull request #37 from tompaana/development

Updates Microsoft.Bot.Builder from 4.2.0 to 4.2.2

Merge pull request #36 from tompaana/development

Merge pull request #35 from jongon/development

Code Refactoring, update to Bot Builder and changing to NetStandard 2.0

Merge pull request #32 from tompaana/development

Updates Nuget badge and version number.

Merge pull request #31 from tompaana/development

Fixes a bug in message routing.

Fixes the credentials bug.

Fixes a aggregation channel and conversation reference handling bug.