Support Arabic, Indic, South East Asian, etc scripts

[davelab6]

While Arabic text input results in shaped input (because its using the electron webkit to render the text), when clicking Add then the result is not shaped, because the samsa engine doesn't apply the shaping needed, so the Vector graphic on the canvas doesn't match:

I expect we'll need @lorp to add a harfbuzz.wasm module to samsa to address this in a simple and holistic way for samsa users like this plugin

[davelab6]

I changed macOS keyboard to "arabic" and then entered u then space then uuu:

ع ععع

And see this:

So it appears to now be working in 0.2.1

[davelab6]

Hmm, RTL doesn't work well, the presence of arabic characters causes all characters to be ordered this way, and the   is shown in reverse order at the start

[khaledhosny]

It seems to be missing both script and bidi itemization and depending on HarfBuzz guessed segment properties which is very simplistic and meant for quick testing only.