Added Pickler and Unpickler that support more flexible .hvz format
Added Pickler and Unpickler that support more flexible .hvz format

In addition to normal pickling behaviour an .hvz file supports
compression and independent loading of metadata and Layout components. A
.hvz file is simply a zip file of pickled HoloViews objects.

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