add new setter for spine positions so that offset_spines can be called anytime
added offset info to despine docstring
add warning to offset_spine and only move visible spines
add tests for offseting spines with despine
fix bad whitespace from despinse work
updated despine call with offset in aethetics notebook
Merge branch 'spineoffsets-with-despine' of github.com:phobson/seaborn into phobson-spineoffsets-with-despine
Update docs and examples with new spine offset functionality