Export feature file via API#184

We would like to export feature file via API so then we can make a manupilation programmatically over it.

I am working on a new product with a small team.
Some members aren’t programmers and didn’t know to use Git or write BDD
documents.
In this case, the testomat is a good tool to let the team co-work with the
online editor. And we can use API to sync the latest .feature file to keep
it updated instead export from web UI.
This is the use case I expected which allows developers easier update it or
add it into CI to track feature requirements changed.