fix(NAPI): Ref-napi ffi-napi added.

[joshuef]

Use NAPI where we can

[coveralls]

Coverage decreased (-0.08%) to 96.417% when pulling 6cd9e4a on joshuef:NAPI into 72d68f5 on maidsafe:master.

[bochaco]

@joshuef , I was testing this with the latest commit of browser from master, and setting in package.json

"@maidsafe/safe-node-app": "git+https://github.com/joshuef/safe_app_nodejs#NAPI"

But I'm seeing some instability which I can reproduce with this dependency only, e.g. I'm able to log in and then after I logged in if I switch the experimental APIs it doesn't finish reloading the authenticator page, or even if I had let's say Patter in another tab it doesn't reload it, or I cannot open a new tab and load a new website. This is not happening with latest commit from master and v0.11.0 of safe-node-app.

Then I went ahead and try to switch experimental APIs right after launching the browser before logging in, and I get this error: {"error_code":-2000,"description":"Core error: Unexpected: Could not connect to the SAFE Network"}