Merge pull request #20 from a-v-l/master

Add offset support for fixed headers
Added fixed header offset support

https://github.com/cferdinandi/smooth-scroll/pull/20#issuecomment-317735
47
Moved variable placement for better performance
Fixed bug that caused animation to stop several pixels short.

https://github.com/cferdinandi/smooth-scroll/pull/15#issuecomment-323807
70
Merge branch 'distance-fix'