AHV Slope/Intercept Graphing Function

[RichardFav]

This will recreate Adam's function (see "plot_all_cell_fits" from the "opendirection" project). Should have the ability to filter by cell types and allow the user to select:

• Bin Size (5 or 10 deg/s)
• Conditions (LIGHT1, LIGHT2 or DARK)

[RichardFav]

For this function:

• Free cells do not need to be matched with fixed
• General exclusion filter will need to be applied (i.e., for RSP regions)
• Only specific filtering that will need to be done is with Freely Moving Cell Type (i.e., AHV)