unlog min,max for axis

[Petr M. <mi...@ph...>]

 	Hello Hans-Bernhard,

in the GPVAL_ patch,

http://sourceforge.net/tracker/index.php?func=detail&aid=1488448&group_id=2055&atid=302055

I've expressed a need for unlogged values in the axis structure. That would 
help both mousing and the GPVAL_ patch: currently gnuplot axis keeps min,max 
from the previous graph but it is not known whether it was log or not 
because the log base of the axis structure changes with the "set" command.

I propose to add these field to axis:
 	graph_min, graph_max
 	graph_base

Thanks,
   Petr