Adds a message indicating the user's ability to :save or :pipe a message
with an unsupported mimetype and also adds a selector widget (similar to
the tutorial).
The selector widget was previously defined in the account wizard module,
so this commit breaks it out into its own module to allow for re-use.
Further, modify the BeginExLine() function to take an argument that
pre-populates the command line, allowing functions to initiate an ex
command without executing it.
Closes#95.
This adds the Mouseable interface. When this is implemented for a
component that item can accept and process mouseevents.
At the top level when a mouse event is received it is passed to the
grid's handler and then it trickles down until it reaches a component
that can actually handle it, such as the tablist, dirlist or msglist.
A mouse event is passed so that components can handle other things such
as scrolling with the mousewheel. The components themselves then perform
the necessary actions.
Clicking emails in the messagelist opens them in a new tab.
Textinputs can be clicked to position the cursor inside them.
Mouseevents are not forwarded to the terminal at the moment.
Elements which do not handle mouse events are not required to implement
the Mouseable interface.
This allows users to use backtab (Shift+tab) to go back through the
fields in the tutorial, like C-K. This then mimics the other methods in
having a forward and backward variant.
Also documented this in the wizard help paragraph.
Many email providers use the imap sub-domain for imap and the smtp
sub-domain for smtp. FastMail is an example of this[1]. This is a small
quality-of-life improvement which automatically replaces imap.* with
smtp.* when going from the imap screen to the smtp screen in the wizard
[1]: https://www.fastmail.com/help/technical/servernamesandports.html
