The memory crusade continues
#690
* dynamically allocate memory for curves. Memory is allocated when when a curve option and valid file are selected, and freed when curves are disabled.
* fix +1/+2 option
* eliminate some copy/paste code.
This saves about 20kb in builds with curves enabled, bringing total CHDK size for a default build of my camera under 300k for the first time in a very long time. Even when curves are enabled, less than 1/2 the previous amount of memory is required. Note that switching through options in the curve menu can bet a bit sluggish, since it loads the file immediately.