Make missing strings translatable, update locale files and German (#19)

* Make a bunch of strings translatable

* Update locale files

* Update German translation

locale/signs_lib.es.tr

@@ -1,25 +1,12 @@
 # textdomain: signs_lib
 Locked sign, owned by @1@n=
+Skims through all currently-loaded sign-bearing mapblocks, clears away any entities within each sign's node space, and regenerates their text entities, if any.=
+There are no signs in the currently-loaded terrain.=
+Found a total of @1 sign nodes across @2 blocks.=
+Regenerating sign entities ...=
+Finished.=
 Write=
-@1 wrote "@2" to sign at @3=
-@1 flipped the wide-font switch to "@2" at @3=
-@1 flipped the unicode-font switch to "@2" at @3=
-
-
-##### not used anymore #####
-
-locked =bloqueada 
-@1 wrote "@2" to @3sign at @4=@1 escribio "@2" en el cartel @3en @4
-Sign=Letrero
-Locked Sign=Letrero bloqueada
-green=verde
-yellow=amarillo
-red=rojo
-white_red=rojo y blanco
-white_black=negro y blanco
-orange=naranja
-blue=azul
-brown=marrón
-Sign (@1, metal)=Letrero (@1, metal)
-Registered @1 and @2=Registrado @1 y @2
-[MOD] signs loaded=[MOD] signs cargados
+Unicode font=
+Wide font=
+Wooden Wall Sign=
+Steel Wall Sign=