v7: Add line styles, mix and match line widths and styles, add redo, more

[shannonturner]

• Closes #30: (Mix and match line widths)
  • While here, it made sense to add line styles (Closes #31), so these can also be mixed and matched.
• Closes #36 (flood fill line width/style, not just color)
• Closes #38 (Station labels above, below)
• Closes #43 (Measure line)
• Closes #35 (Add redo)
• Closes #59 (Rectangle station overlap on a singleton until next call to drawCanvas)
• Closes #46 (Remove anti-aliasing "Eraser marks", RIP, I will miss you but I'm probably the only one)