Add onSetPosition callback

Consider adding a callback for setPosition.  I've used this to move buttons and dots based on slide contents/heights.
Update README.markdown
Update index.html
Added opacity variables to `slick` settings.

Opacity settings could not be overridden.
Merge pull request #644 from gwa/master

Added opacity variables to `slick` settings.
Merge pull request #717 from kenwheeler/1.3.12

1.3.12
Bumping version
Emergency Hotfix For Non Infinite Single Slide
Fixing non-infinite with uneven values v1
Fix progressive lazy loading issue

Having multiple slick carousels on a page with lazy loading causes the progressive lazy loader to miscount the number of slides. This fixes the issue
Merge pull request #758 from cjbos/patch-1

Fix progressive lazy loading issue
fix  RTL drag and swipe #674
adding calculation for carousel width in breakpoints

The breakpoints in slick are better suited for Walmart.com carousels if
we let them adjust based on carousel width in addition to window width.
adding responsive target settings

with default being window, and options slider and min as well.
adding slider and window width vars
Fixes #769
Fixes #760

Also adds non animated slickGoTo
Fixes #685
Fixes #691
Merge pull request #765 from rollstudio/master

fix RTL drag and swipe #674