improve typings, install via typings cli

[kruczy]

this will allow preact typings to be installed globally via typings cli
typings install github:developit/preact --global

the reason to do it is that JSX typings will not work if they are not global

the next step would be to add a reference in typings/registry

[developit]

@kruczy in order to make typings install preact work, should we be including typings.json in the npm release? Or is that what their registry does?

[kruczy]

@developit there will need to be an entry in the registry pointing at preact github repo, I don't think it needs to be included in the dist npm package, will make a pr against the registry to include preact there

[developit]

Perfect!