Version 1.10.4

This is a minor bug fix release including a number of crucial fixes
for issues reported by our users.

Enhancement:

• Allow setting alpha on Image/RGB/HSV and Raster types in bokeh
  (#2680)

Fixes:

• Fixed bug running display multiple times in one cell
  (#2677)
• Avoid sending hover data unless explicitly requested
  (#2681)
• Fixed bug slicing xarray with tuples
  (#2674)