The following functionalities are added to configure aerc ui styles.
- Read stylesets from file with very basic fnmatch wildcard matching
- Add default styleset
- Support different stylesets as part of UiConfig allowing contextual
styles.
- Move widgets/ui elements to use the stylesets.
- Add configuration manual for the styleset
Especially if one tries to interact with all marked messages there could be
the case that not all headers are fetched yet, hence the messageInfo is still nil.
This segfaults a lot of commands which in principle only need the uid to complete.
If we switch to uids, this issue can be alleviated for those commands.
* :save takes a path and saves the current message part to that location
* :pipe is the same as pipe on the account page, but uses the current
message part rather than the whole email (ie :pipe gzip -d)
* Refactored account:pipe and extracted common pipe code to
commands.util.QuickTerm
* Added helper command aerc.PushError
