Create multicolor highlight capabilities on mapHub

[paradalis]

Some highlight categories should be designed to support multicolor highlights. These are indicated in the database file "UBHub Database Feb 2018" on the "mapbuttonTable" tab as follows:

1. the column "marker_colors" indicates which column from the tab "participationTable" will contain the data for the highlight designation (this is pretty much always the same column). Null values indicate a binary highlight of either marker_5_orange_39x59.png (highlighted) to marker_0_grey_39x59.png (not highlighted). It should already be set up this way by default. For all others, read on:
2. the column "marker_colors" lists the designation for each color, separated by commas and starting with the brightest highlight (5_orange), then next brightest (4_ltorange, 3_yellow, etc.) If a category has less than five designations, then it will use only the brighter colors and not reach the lower colors.
3. These highlights will use the map marker images that are in the images folder, starting with marker_5_orange_39x59.png and continuing along to marker_1_blue_39x59.png, with 0_grey only used for non-highlighted markers, as before.
4. These new multicolor highlights will need a map key somewhere. The designations from the "marker_colors" can be used to create the key.

[joshuacassidygrant]

Finished with 1-3, still need to work on a map key.