Migrate project from JavaScript to TypeScript

[aralroca]

In this issue #302 @croutonn started supporting TypeScript by adding the types. However, ideally, the project should be migrated to TypeScript so that the types will generate themselves and be more robust. I created this issue for this. Ideally, by version 1.0.0 the project should have been migrated to TypeScript.

I started migrating the project to TypeScript under the branch 1.0.0-experimental, taking advantage that I am making structural changes for version 1.0 as the issue #303.

I did a prerelease 1.0.0-experimental.11 with all the API migrated to TypeScript if somebody wants to test it (everything related to the webpack loader is still missing, which will have version 1.0 instead of the "build step".).

[aralroca]

Closing this. Already implemented on 1.0.0-canary.1. The 1.0 will be released in approximately 1-2 weeks. 😊