Add ability to use alias e-mail addresses

This change allows for very short writings of mail-addressees. Simply
add a new mail-alias in the file ~/.config/mutt/mail_aliases in the
following form and I'm ready to use that alias.

    alias foo Foo Bar <mail.Foo.Bar@example.com>

.config/mutt/muttrc

@@ -77,3 +77,5 @@ macro index <f3> "<sync-mailbox><enter-command>source $XDG_CONFIG_HOME/mutt/acco
 # Source my default account
 source "$XDG_CONFIG_HOME/mutt/account.info.nehrke_felix.muttrc"
 #source "$XDG_CONFIG_HOME/mutt/account.com.gmail_nemoinho.muttrc"
+
+source "$XDG_CONFIG_HOME/mutt/mail_aliases"

.gitignore

@@ -1,4 +1,5 @@
 README.*
 !README.adoc
+.config/mutt/*_aliases
 
 __pycache__