double underscore. Added #includes for dependent files.
* popt.c: Likewise.
* popthelp.c: Likewise.
* tree.c: Moved a macro from tree.h to here, as it is useless
outside tree.c.
text into the command line.
* main.c: Use command_insert() instead of stuff(). This ensures
that the names in the command line are quoted.
Reported by Arpad Biro <biro_arpad@yahoo.com>