v3 greater refactor (#43)

BREAKING CHANGE: api changed
* chore: change exported api

* refactor: change animationManager

* chore: remove demo

* docs: update readme

* docs: update readme

* feat: add `misc`

* refactor: remove tests

* feat(misc): add `scrollTo` function
similar to `scrollBy`

* feat(misc): add `isElementInRange`
returns `true` if element is visible from its container #14

* docs(readme): fix typo

"design" -> "designed"

* fix: missing module in package.json
ts-node

* test: add cypress
Squashed commit of the following:
    test: add screenshots for readme
    test: refactor tests
    test: add basic cypress tests

* refactor: change position to scrollPosition

* docs: update README

* chore: remove browserstack

Author: David Perez Alvarez

.npmignore

@@ -16,3 +16,4 @@ webpack.config.js
 .prettierignore
 .prettierrc
 tslint.json
+cypress

.travis.yml

@@ -11,8 +11,3 @@ after_success:
 branches:
   except:
     - /^v\d+\.\d+\.\d+$/
-addons:
-  browserstack:
-    username: "davidperezalvare2"
-    access_key:
-      secure: "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"