Summary
Close #72 : Convert all sources and test files to typescript

This PR is working in progress.

Here is what I could do so far:

• Convert to the core and test files to typescript
• All unit tests passed

Now I still have the trouble for running yarn readme and yarn examples. I'm working to resolve theses problem. But I don't have much ideas yet. Any help would be very appreciated.

Test plan

• I need to fix the issue of two commands above
• Because all unit tests were passed. So I need make sure all the examples files are run without problem
• Implement and make sure this version typescript is all compatible in the project that has already used the actual version of veggies

Thanks.
Duy