Fix for robust Bokeh version comparison
Fix for robust Bokeh version comparison

Fixes Issue #310

vascotenner/holoviews,basnijholt/holoviews,vascotenner/holoviews,ioam/holoviews,vascotenner/holoviews,basnijholt/holoviews,basnijholt/holoviews,ioam/holoviews,ioam/holoviews