don't read me

Bring contribution guidelines up to date

Implemented concatenate operator (&) and function (concatenate())

This is important because + only adds numbers, so we did not have a way
to concatenate before. Operator inspired from Ada. How it works: array
& string will join the array, array & array concatenates element-wise,
string & string will concat the strings.

Add CNAME

Small docs updates

The fix for mavoweb#32 (248f394) basically broke editing. This fixes …

…it again

Enabled ES2015 transpiling instead of specific features

Semi-stable, I think