Plus42 Equations, Preview Release

[Thomas Okken]

New update:

1. A few improvements in drawing axes, tick marks, and labels.
2. In equations, FCSTY and FCSTY are now recognized as being each other's inverses, so they can be handled by the direct solver.
3. You can now mark points using ENTER, and when two points are marked, you can then run the solver with those two X values as starting guesses (press Shift-7), or run the integrator with those two X values as limits (press Shift-8), or zoom in with those two points marking the corners of the new view rectangle (press 0).
4. When exiting, now writing the state file using a temporary name first, and renaming it to *.p42 only when successful. This way, a crash during exit won't wipe out all of the previous state.

Feature-wise, that's it for 1.0. I guess that makes this the first beta!