This does the same thing as right clicking, but provides a visual indicator.
The icon disappears if the window is too small or docked (right click keeps working).
This makes code easier to read and more consistent between C++ and Java.
Also update clang-format settings to always add a line break (even if no braces are used).
This reuses many pieces of the current simulation GUI. The common pieces have
been refactored into the libglass library.
The libglass library is designed to be usable for other standalone data
visualization applications (e.g. viewing data logs).
The name "glass" comes from "glass cockpit", as the application features
several multi-function displays that can be adjusted to display robot
information as needed.
