- move all mu4e startup functions to mu4e-utils
- add `mu4e' function to mu4e.el that call these mu4e-utils function
- now easy to start mu4e without showing ui
- mu4e~proc-is-running moved to mu4e-proc
- made mu4e-read-option a bit smarter
- renamed some more functions from mu4e- => mu4e~ (i.e.., mark them private)
- move logging vars to mu4e-utils
- some typos fixed
- add mu4e-ask-maildir-check-exists, which is like mu4e-ask-maildir, but
checks that the maildir exists, if not, ask the user
- mu4e-utils.el: s/mu4e-offer-action/mu4e-choose-action/, and return a
function now, rather than executing it directly
- mu4e-view.el: implement the attachment handling function in terms of
mu4e-choose-action, and each other. also fix some small issues.
- add mu4e-toggle-logging to enable/disable logging
- add mu4e-show-log to view the log buffer, and bind it to '$' in the
main/header/view buffers
- add a note about it to the doc (mu4e.texi)
- make mu4e-log the the new logging function, use colors to distinguish
incoming/outgoing data
- only keep last 1200 lines of log in the log buffer
