fix: rare crash placing new bases

Crashes can occur in two cases:
1) If a mouseover triggers between base being named and
BuildNewBaseState destructor call.
2) If a mouseover triggers between confirm new base cancellation and
BuildNewBaseState destructor call.

Solution is to swap between globeHover handler and an empty handler as
necessary.
new option: in-research aliens take containment
add new string to language_id.html
add Polish translation; thx radius75!
Merge remote-tracking branch 'upstream/master' into alien-research-in-containment
combine both alien containment options into one

combine alienContainmentHasUpperLimit and alienResearchUsesContainment into one alienContainmentLimitEnforced option
zero handler

Forget using an empty handler, you can simply zero it.
missing include

Fixes bug 180
Merge pull request #562 from cfailde/include

missing include
Merge pull request #554 from cfailde/newbase

fix: rare crash placing new bases
Merge remote-tracking branch 'upstream/master' into alien-research-in-containment

Conflicts:
	src/Basescape/ResearchInfoState.cpp
simplify item removal/restoration logic
fix boolean logic and some grammar
fix typo in lang files
Merge pull request #556 from myk002/alien-research-in-containment

addition to containment limits option: in-research aliens take containment
Fixes some memory leaks
Fix small bug in melee checking
Merge pull request #564 from louisdx/memoryleaks

Fixes some memory leaks