Instead of having AUTHORS.src and copying that to a new AUTHORS
file with git log information appended to that have a single
AUHTORS file and update it in place with git log info.
Move Acknowledgements to a separate file to enable some code
simplification and improve maintenance and discoverability
for acknowlegements.
Convert the Acknowledgements file to Github flavored markdown
and display it in rich text using QTextBrowser.
Add Acknowledgements.md to NSIS installer
João Valverde