Updating release notes for 5.1.4

Updating release notes

Minor comment changes in release script

Updating release notes

Updating release notes for v 5.1

Updating release notes for 5.0.3

Pointing release script to msbuild in buildtools installation folder.

This could be better and more generic

Updating release notes for 5.0.1

Implemting async methods on AuditEventListener (sync for now)

Correcting path to msbuild to support c#7