* Fixes#4574.
* Removes the usage of atoi as any failure returns 0.
* Adds checks for cases of invalid data.
* General cleanups and fixes.
* Fixes the import database documentation.
Thanks to @Skormie!
Add db/import-tmpl/ and add all file that could currently be
overwritten, (please add note if a db is missing)
db/import folder is created by "make import" just like conf/import and
msg_conff/import, (didn't found the visual equivalent)