feat: Add Nodejs v12 support and move from ref to ref-napi

Node is moving to NAPI so everyone and everything is moving to -napi to avoid compatibility issues.
This is required for NodeJS v12 compatibility.

- update segfault-handler for nodejs 12 compatibility
- updates nodejs version in travis.yml

.nvmrc

@@ -1 +1 @@
-8.9.3
+12.13.0

.travis.yml

@@ -3,8 +3,7 @@ language: node_js
 notifications:
   email: false
 node_js:
-  - '9'
-  - '8'
+  - '12'
 install: npm install
 after_success:
   - npm run build

README.md

@@ -93,7 +93,8 @@ You have several options to get your image:
 
 Some example are available in the examples directory, when you have cloned or downloaded the complete project from github.
 
-Checkout this project then run `npm run develop` and run `node examples/camera.js`.
+
+Checkout this project then run `npm run install:examples && npm run develop` and run `node examples/camera.js`.
 
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