Re-add LICENSE.txt and README.txt
Remove .empty files and update .gitignore
Add nupkg-only only target to build.ps1
Remove pack.bat - use ".\build.ps1 -Target nupkg-only" instead
Revert "Re-add LICENSE.txt and README.txt"

This reverts commit 735d1b5ea404d144bfccf5877f6fbff9b867bed8.
Add license and readme in root - easier to find
Update License path