Merge pull request #3 from alfredosalzillo/dev

version bump to 2.1.0 and added changelog for the new version

feat(useContext): added useContext hook to use the BuildContext inside other hooks

fix(HookWidget): corrected the createState return type

added test for HookWidget

fix(HookWidget): is now the base widget for build hook

feat(HookWidget): add key support

Merge branch 'dev' of https://github.com/alfredosalzillo/flhooks

add codecov badge

CI: remove coverage dependencies and fix travis config

CI: add codecov coverage support

fix(use): fix a spelling typo in asserts

feat(HookWidget): add HookWidget to use hooks in class instead of function, class Widget have better performance.

Merge branch 'master' of https://github.com/alfredosalzillo/flhooks

Fix errors in readme and changelog