Appion

I wrote a new picker for manually selecting helices. I did as many tests as I could think of, and I don't think this is breaking anything.
Instead of defining a helical step and filling in between 2 points, this allows you to pick along an entire helix, and then define a helical step size when making a stack. This makes picking much faster, and allows you to make stacks that have different helical step sizes from the same set of picks.
To use this helical picker, select the "Pick along helices" option in the manual picking webform. It won't let you set a helical step size at this point. In the gui, plot points along the center of a helix (as many as necessary), and then click on the "Add Helix" button at the bottom. The plotted points along the helix will turn red.
Then when making a stack with the makestack2 webform, select these particle picks, and enter a value in the "helical step" option (this value is in angstroms). The "Helical Alignment" options at the bottom should still work when this is selected.
In order for this to maintain the ability to make substacks or frealign stacks, a new particle selection run is created in the database along with this stack, keeping track of the location and angle for every particle in the stack. There is also a new "helix" column in the ApParticleData table that will keep track of which particles came from a particular helix. I hope to use this information in future 2D alignment and reconstruction scripts.