
   input (filename)

   execute a series of commands given in the file.

   Two special examples:  
   ~/.manarc is loaded on startup, which give the user a place to
   define personal macros, or interesting variables, etc.

   If mana is called in the form "mana file", the file is loaded
   (after .manarc) before the user is given the command-line prompt.
   This can be used to invoke mana in a shell script, but care should
   be taken in a shell-script that the file ends with the word "exit"
   or "quit", or strange things may happen...

