Switch to `PascalCasing` for component names, in next major version

[jasongitmail]

Svelte and NativeScript use PascalCase for components by convention.

But Svelte Native uses camelCase and is inconsistent with these.

While not a big deal, consistency would make it feel more polished, smooth initial usage for new users, and allows copy and paste from NativeScript docs for various items.

[matthewblott]

Definitely this. I actually prefer using camel case but pascal case is more consistent and just 'feels' right. It also makes migrating from other technologies easier.