JM-15S - feedback welcome

[jwm]

Some Changes

- Added keys to swap stack with alternate stack and push value to alternate stack and pop value off alternate stack (under cos and tan). The alternate stack will be saved and restored on XEQ so you can use it to store values you don't want clobbered, additionally it will be the staging area for constructing/editing vectors and matrixes. right now via the A,B,8 keys. I am unsure how the symbols should look to be obvious what they are doing.

- Since [XEQ][A] is just as easy as [g][A], I moved the user definable names off of a shift key freeing up some prime real estate. A 'USER' mode like the 15C can be used for even easier access.

- Made use of that big gap between the 2nd and 3rd row to put all the special registers. This also frees up the top row for use with STO/RCL and equation solving, such as the time-value-money 12C feature. By putting PREC on STO and LASTx on RCL, changing the precision is [n][STO][STO] and LASTx is [RCL][RCL] which are both quite easy. This makes hiding the display mode under a menu less painful as you can easily change precision while keeping the display mode the same. (image has LASTx in old position)

- use squiggly arrows when a numerical operation happens vs a straight arrow for just pushing values around.

- switched the colors to save printer ink and be easier to read when the black ink bleeds over, when printing on vinyl different colors can be used. I feel it looks much less cluttered now. I need to heuristically expand some of the math fonts as the nth-root and integral and ye^{ix} don't quite pop as I'd like.

   

Using a paper overlay for testing is surprisingly usable. I can feel and press the keys through the paper just fine without losing the nice tactile switch.