Hypergrid core demos & documentation

Hypergrid demos have been moved to a new demo folder which always contains the latest versions.

https://fin-hypergrid.github.io/core/demo

For historical versions, substitute the version number for demo. For example, to see the 2.1.15 demo specifically:

https://fin-hypergrid.github.io/core/2.1.15

For the other demos, add the specific demo's filename. For example:

https://fin-hypergrid.github.io/core/demo/basic.html https://fin-hypergrid.github.io/core/demo/computed-column.html https://fin-hypergrid.github.io/core/demo/example.html https://fin-hypergrid.github.io/core/demo/multiple-grids.html https://fin-hypergrid.github.io/core/demo/row-props.html
And again, for historical versions of the other demos, substitute the version number for demo as above.