gEDA-dev: Added attribute names to system-gschemrc.in

[Ales Hvezda]

[snip]
>	The email= attribute has been merged with author=.
>
>http://geda.seul.org/wiki/geda:master_attributes_list#email
>http://geda.seul.org/wiki/geda:master_attributes_list#author

Also, much to my surprise, dist-license and dist-use attributes are not
part of the master attribute list, so I've added them now. 

http://geda.seul.org/wiki/geda:master_attributes_list#dist-license
http://geda.seul.org/wiki/geda:master_attributes_list#use-license

							-Ales