add more heliport map links

[gbinal]

• https://www.google.com/maps/place/38%C2%B052'27.4%22N+77%C2%B001'16.9%22W/@38.8740696,-77.0223349,158m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d38.874279!4d-77.021366?hl=en
• https://www.google.com/maps/place/38%C2%B054'54.4%22N+76%C2%B058'23.9%22W/@38.9150194,-76.973879,157m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d38.915111!4d-76.973308?hl=en
• https://www.google.com/maps/place/38%C2%B055'04.4%22N+77%C2%B002'17.2%22W/@38.9176844,-77.038506,158m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d38.917896!4d-77.038108?hl=en
• https://www.google.com/maps/place/38%C2%B056'05.4%22N+77%C2%B004'29.4%22W/@38.9342228,-77.0728406,131a,35y,289.06h,55.24t/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d38.934824!4d-77.074835?hl=en
• https://www.google.com/maps/@38.8352125,-76.9847911,158m/data=!3m1!1e3

[UndisclosedLocation]

This map of helo routes and heliports may help you https://aeronav.faa.gov/content/aeronav/heli_files/PDFs/Balt_Wash_Heli_11_P.pdf

[gbinal]

Thanks, @UndisclosedLocation. It's still on the to do list, though I'm moving that to #50.