0.3.1.0 Multi-Select support and QoL features

Added Multiselect features, with the following functions

• Ctrl+Left-click a token to add or remove it from a group.
• Ctrl+Left-click and drag a rectangle to add most things to a group. Some tokens (like player tokens for the GM, or locked tokens) can't be added this way, but can be added when explicitly clicking the token.
• Ctrl + 1-9 will save a selected token or group for later. Pressing 1-9 will recall the selection group, similar to a Real-Time Strategy game. The group selection UI also has buttons to save groups with.
• Dragging an item in the active selection group will move all items. Maintaining their relative positions.
• The group selection UI allows you to add damage to all selected, remove tokens with damage over a threshold, and edit all tokens in a group.
• Selection groups, and group saving is available to players as well as the GM. So players can move the party as a group.

In addition, a number of quality of life and bug fixes have been added:

• Fog of war on bright colored maps will now appear as a dark transparent shade for the GM
• Players on whiteboard maps now see fog of war as a opaque black, rather than looking like empty grid space.
• Added an add-damage function to selected token, and made the overall selection menu a little more compact.
• Added smooth-scrolling of the map while an arrow/wasd key is held. This also makes controller navigation better.
• Added a campaign option to always sort rolls high-to-low by default. If enabled, individual rolls can be reverted to as-rolled order by clicking the descending bars icon in the upper left of the roll result (and vice-versa to sort a roll that's not sorted)
• When you have multiple separate-rolls in a single batch due to split dice (like rolling 2d20 with the default config) there is now only one header displaying what was rolled.
• There is now an option to enable player control of GM tokens, so the GM can grant party control of NPCs as needed.
• Fixed an issue where erasing fog erased few extra pixels around the selection area, including 0-width erases, making it possible to leave little jagged edges in snap mode.
• Previous quiet release 0.3.0.3 added a function to toggle sorting on an individual die roll when clicked on. It also fixed a couple of crashes introduced in the prior release.

Edit: Minor Patch 0.3.1.1 released, drastically improves the responsiveness of drawing and token moves, and fixes a few bugs from the prior release with moving Player-Controlled-NPCs, and a bug with the new group-image-assignment buttons.