Mostly a cosmetic update.

• In the margins of the source windows, allow CTRL+DoubleClick to do a quick RunToLine or RunToAddress.
• Add --gdb-program and --gdb-arguments to command line to override settings from Seer's config.
• Fixed a rare bug with blank lines from gdb causing a segv in GdbMonitor.
• Fixed bug specifying path to "rr" debugger.
• Add option to reload source file if it changes.
• Tighten up the layout by removing some needless whitespace.
• Move gdb messages to a tab in the breakpoints window.
  • Options to raise on every message, never, or important messages.
• Add C++ level (11 or 17) depending on qt5 or qt6 compile.
• Fixed up column resizing for the Variable logger (#173)
• Use monspace font, where it makes sense (#175)
• Allow copy to clipboard (#176)
• Fixed hovering a variable name and value (#179)
• Add nested struct viewing in "locals", "arguments", "logger", and "tracker" tabs. (#180)