Updated build process to include engine, release notes and docs building.
Added base note set.
Added initial notes for 6.1.
Added .md as text extension to .gitattributes.
Added remaining notes for 6.1-dp-1.
fixed bugs in release notes builder
completing merge
Tweaks to formatting of docs md files.
used livecode css to style release notes pdf
Merge branch 'feature-automated_build' into develop