Operation Valgrind

[yakra]

old #	redone	skip	wait
1	Datacheck main	HGEdge not necessary after bf525b5	read_wpt WaypointQuadtree
2	all
3	read_wpt: new comments only TravelerList: new comment only		everything else
5 (not 4)	Datacheck		main
4 (not 5)	all
6		delete in sqlfile1 instead of main

[yakra]

TravelMapping#451 (comment)

Added 7 more commits that help make siteupdate more "Valgrind clean", avoid invalid reads & writes, and plug lower-impact memory leaks.

Class destruction for bigger-ticket items is still subject to change, so I'm holding off on pushing to master for now.

Said bigger-ticket items were addressed in TravelMapping#592, via class dtors when TMArrays go out of scope.
...Rather than seek over-complicated ways to manually delete everything concurrent with other tasks (most likely writing the SQL file). LOL, and it doesn't contribute to the Total run time figure if it happens at the very end after that, as we exit main. If that's arguably cheating, it's a kind I'm OK with. :)

Siteupdate is valgrind clean; no need to keep this issue around anymore.