fix: cannot read property 'split' of undefined (gajus#225)

* fix: cannot read property 'split' of undefined

* fix: lint error in getClassName

* fix: lint error in getClassName

feat: respect exclude setting in JSXElement transform (gajus#215)

BREAKING CHANGE:
* exclude logic is used to exclude JSXElement containing files

fix: force release

BREAKING CHANGE:
* babel 7 requirement

fix: update test fixtures (gajus#212)

* fix: update test fixtures

Fixes gajus#211

* chore: assert exception on use with missing import

fix: update build command and dependencies (gajus#210)

* fix: update build command and dependencies

This commit updates the presets and plugins used in the build-helper
run script to use equivalent v7-packages from the @babel namespace.

* fix: update demo deps and config

Fixes gajus#204

style: sort alphabetically

fix: do not commit package-lock.json

See npm/npm#20603

fix: correct semantic-release usage

fix: use t.clone helper (gajus#151)

fix: update postcss to v6.0.13 (gajus#133)

Tests seem to pass, also tested locally and seems to work fine in a real project