mu4e-views Updates

This file provides an overview of what is new in each mu4e-views version. Since I only started keeping track after version 0.5, this is incomplete.

Version `0.6` (development version)

supports mu version 1.5.x and 1.6.x
new view methods:
- view emails in browser with filtering
- view email as pdf (relies on external tool such as html-pdf)
one-time switching of viewing method to temporarily view the current message using a different view method without changing the viewing method (the next email to be opened will be shown using the standard viewing method selected by the user)
dispatcher view method allows to let mu4e-views select an appropriate view method for each email based on a set of rules, e.g., show non-html emails using the build-in mu4e view method or filter out remote content for all emails except for senders from a whitelist.