Further build script tweaks

Prep for beta902 release

Merge branch 'tillig-rtm-project-update'

Update package summaries

Rename SwaggerUi project to Swashbuckle (for Nuget)

Upgrade AspNet to beta7

Target AspNet beta6

Update project.json to prevent specific System.Xml.XPath version in n…

…uspec

Bump version to beta2