added comments / minor code changes, fixes #4
fixed some problems with the demo markup, optimized the demo
added configuration variables, fixes #1 and #5
optimized animations
added a namespace variable and a separate scss version with icons included, use the version with icons for the demo, fixes #6
fixed formatting of README.md, fixes #2
fixed jumping when overlay is closed
added a initial delay in which the full image can preload
finalized the demo page and added a description to the README.md, fixes #3
Merge branch 'dev'