Contributors - update list

Thank-you to everyone that has contributed towards this release!

Merge pull request sonic-pi-net#2309 from emlyn/patch-6

Fix links and formatting in Info window History tab

GUI - update startup h1 colour to match theme

Build - further automate windows build process

Still more work to be done here!

Doc - fix mistake in midi out docs

FX - add experimental guitar saw synth

Will potentially be used as a base for future pitch-detection-style synths/FX

GUI - fix version number displayed in info window

changelog - update release date for v2.11

Changelog - minor final tweaks

GUI - update version string in doc