don't crash when fromNode is 0 for some reason

(it was a cyberdisk)
some code clean to remove warnings
If deleting last save from load menu, don't show it any more.
fix interrogation popups

no longer displays racial information twice.
no longer displays alien interrogation repeatedly.
fix for previous fix
first mission is sectoids.
update camera center from inventory screen.
sanity check that variable.
a fix or two for cydonia
larger scale cydonia fix.

fixes the following:

- sets the "aborted" flag properly now, so it will actually kill the units
outside the exit. area instead of dragging them along for the hell of it.

- aliens remaining on the surface will no longer follow you down into the base!

- save/load now works in the second stage of the mission, as new enemies are
given proper IDs above 100000, and leftover items are "put aside" to an invalid tile

- alien bases/cydonia will no longer have "strange holes" in 20x20 modules.

- the briefing screen will no longer be strange colours.

with thanks to Cizra for his test cases.
fix ammo thing and detection rates.
Merge branch 'master' of https://github.com/xanscale/OpenXcom.git
Merge pull request #374 from hmaon/nodesel_crash

don't crash when fromNode is 0 for some reason
Merge pull request #383 from rohitnirmal/load-delete

If deleting last save from load menu, don't show it any more.
yet another fix for research popups.

if the base's available research has dependencies on this research,
or if the base's available research is unlocked by this research,
and it isn't unlocked by another discovered research or it's dependencies,

then unlock this research, and possibly it's dependencies, depending on if
the discovered research unlocks the dependent research in question.

simple, right?