On NewFlags events, the threads in Collection were not being updated, so
if an envelope's seen status was toggled the thread's unseen count was
not updated, and thus not reflected in the UI even though the
envelope's new flags event was registered properly.
Execute user provided command invocations $CMD such as `editor_cmd` with
`/bin/sh` as `/bin/sh -c "$CMD"
Previously, user commands were split by whitespace which must trigger
erroneous behavior if quotes are involved.
conf_override! wraps struct definitions and defines a secondary Override
struct that wraps each field in an Option. The macro mailbox_settings!
is used to select settings from an account & mailbox index. If a user defines an overriding setting, the macro returns the override instead of the immediately next in the hierarchy setting.
The selection is done for a specific field as follows:
if per-folder override is defined, return per-folder override
else if per-account override is defined, return per-account override
else return global setting field value.
Refactor Collection from melib to hold what folders have what envelopes.
Frontend accounts will now have a FolderEntry for each logical folder
and will unify many Account fields into one and eliminate a lot of
duplicate/dead code.
Use FolderHash directly as a cursor type for folders within an account
isntead of having a usize (being the order of the folder within the
account) and figuring out the folder_hash everytime it's needed.
Add OfflineListing for offline accounts and AccountStatusChange event.
Subscription status was checked/modified in various places, whereas now
the universal truth is the `BackendFolder::is_subscribed()` method set
by the backend when a folder is created. The `Account` struct passes a
closure to the backend constructor that determines whether the folder is subscribed or not according to the user configuration.
- If subscribed_folders field is empty, then all folders are subscribed.
- OR check explicit folder configuration
- OR check if folder path matches to a glob in subscribed_folders.
Merge ui crate with root crate.
In preparation for uploading `meli` as a separate crate on crates.io.
Workspace crates will need to be published as well and having a separate
`ui` crate and binary perhaps doesn't make sense anymore.
