Implement testing in React 0.14, 15, 16, add wallaby.js, use enzyme

.gitignore

@@ -6,3 +6,17 @@ lib
 .nyc_output
 coverage
 es
+test/**/lcov.info
+test/**/lcov-report
+test/react/0.14/test/components/*.spec.js
+test/react/0.14/test/utils/*.spec.js
+test/react/15/test/components/*.spec.js
+test/react/15/test/utils/*.spec.js
+test/react/16.2/test/components/*.spec.js
+test/react/16.2/test/utils/*.spec.js
+test/react/16.3/test/components/*.spec.js
+test/react/16.3/test/utils/*.spec.js
+test/react/16.4/test/components/*.spec.js
+test/react/16.4/test/utils/*.spec.js
+test/react/**/src
+lcov.info

.travis.yml

@@ -1,8 +1,20 @@
 language: node_js
 node_js:
   - "8"
+before_install:
+  - 'nvm install-latest-npm'
+env:
+  global:
+  - TEST=true
+  matrix:
+  - REACT=0.14
+  - REACT=15
+  - REACT=16.2
+  - REACT=16.3
+  - REACT=16.4
+sudo: false
 script:
   - npm run lint
-  - npm test
+  - npm run test:ci
 after_success:
   - npm run coverage

CONTRIBUTING.md

@@ -35,11 +35,25 @@ npm run build:umd:min
 
 ### Testing and Linting
 
-To run the tests:
+To run the tests in the latest React version:
 ```
 npm run test
 ```
 
+To run in explicit React versions (the number is the version, so `test:16.3` will run in React version `16.3`):
+```
+npm run test:16.4
+npm run test:16.3
+npm run test:16.2
+npm run test:15
+npm run test:14
+```
+
+To run tests in all supported React versions, `0.14`, `15`, `16.2`, `16.3`, `16.4`,
+```
+npm run test:all
+``` 
+
 To continuously watch and run tests, run the following:
 ```
 npm run test:watch