Updated translation

Updated latest strings
Removed blinking grey area in the "Hidden movement" state;
Centered "Loading game" and "Saving game" messages;
don't need save _inDogfight flag
Merge pull request #617 from Xracer/patch-1

Updated translation
Merge pull request #620 from redv/interface6_hidden_movement

UI improvements: fix for wide screens
Merge pull request #622 from redv/fix_dogfight

Fix: Bug report #237 - Interceptor can never enter air combat again, when game was saved while in air combat
Fixed compilation error on GCC
Fixed "Battlescape/Map.cpp:89:59: error: incomplete type 'OpenXcom::Screen' used in nested name specifier'"
Merge pull request #623 from winterheart/fix-compile-gcc

Fixed compilation error on GCC
(Hopefully) improve a few Dutch translations, add missing ones up until cyberdisc autopsy
Add several more ufopaedia and mission briefing texts, including game over/endgame stories!

Changed a few texts for consistency to the informal "je" form.  In some sentences formal and informal were even mixed!

Use UTF-8 rather than Latin-1.
More translations, up until STR_ACCESS_LIFT_UFOPEDIA