fix LoS

 - when a calculation is made to a potentially spotted enemy unit,
   but another unit is blocking that LoS, the trajectory stops at
   that unit and TileEngine::visible() returns true.
 - this fix includes a last check to ensure that the unit that's
   attempting to be spotted is really the unit that the trajectory
   stops at. If not, return false.
bigger bases have bigger detection chance...
Update Zoom.cpp
only flying UFOs should do detection.
The Great Language Cleanup (translations will be buggy until translators update them!)
- Combined all sentences into one string
- Fixed all strings with trailing whitespace
- Removed various unused strings
- Fixed incorrect original strings
- Added strings for Construction Complete, Smoke, Plasma Beam, Aliens Killed by Crash
missing include directive in ActionMenuState.cpp
ifdef FLC rendering placement

These issues may be system and/or SDL version dependent.
More bug reports may be needed to work this out.
Merge pull request #678 from atlimit8/FlcWinLinSplit

ifdef FLC rendering placement (should fix bug #294)
Merge pull request #677 from atlimit8/Fix-ActionMenuState.cpp

missing include directive in ActionMenuState.cpp
Merge pull request #676 from GixG/compilWarning

Fix bug #295
Merge pull request #661 from kevL/visible_fix

fix LoS
Merge pull request #665 from kevL/detect_xbase_fix

bigger bases have bigger detection chance...
Added "Mersenne Twister pseudorandom number generator"
Fixed compiler errors.
Derp
Clicking on text moves caret now.
Fixed some UI strings.
Fixed left-hand sprites not working with mods.
Compiler errors
Wrong enum
Fix compiler warnings
tidy up some code a bit