Add missing entries.

stepmania/Themes/default/Languages/en.ini

@@ -614,6 +614,7 @@ BGBrightness=Brightness
 Background Options=Background Options
 BarDrain=Bar\nDrain
 BatLives=Bat\nLives
+Base Difficulty=Base Difficulty
 Bookkeeping=Bookkeeping
 Calibrate Machine Sync=Calibrate Audio Sync
 CPUSkill=CPU\nSkill
@@ -621,6 +622,7 @@ CelShadeModels=Cel-shaded\nModels
 Center Image=Center Image
 Chaos=Chaos
 Characters=Characters
+Choose=Choose
 Clear Bookkeeping Data=Clear Bookkeeping Data
 Clear Machine Edits=Clear Machine Edits
 Clear Machine Stats=Clear Machine Scores
@@ -707,6 +709,7 @@ Group=Group
 Hands=Hands
 HiddenSongs=Hidden\nSongs
 Hide=Hide
+High Meter=High Meter
 Holds=Holds
 Home/End: jump to first/last beat=Home/End: jump to first/last beat
 Input Options=Input Options
@@ -721,6 +724,7 @@ Language=Language
 Layer=Layer
 LifeDifficulty=Life\nDifficulty
 LifeType=Life\nType
+Low Meter=Low Meter
 M: Play sample music=M: Play sample music
 Machine Options=Machine Options
 Main title=Main title
@@ -789,6 +793,7 @@ Servers=Servers
 Set P1=Set P1
 Set P2=Set P2
 Set modifiers=Set modifiers
+Set Mods=Set Mods
 Shift + P: Play current beat to end=Shift + P: Play current beat to end
 Shift + Up/Down: Drag area marker=Shift + Up/Down: Drag area marker
 Shift + number: Lay mine=Shift + number: Lay mine
@@ -807,8 +812,11 @@ ShowSongOptions=Show Song\nOptions
 ShowStats=Show\nStats
 SmoothLines=SmoothLines
 Center1Player=Center\n1 Player
+Song=Song
+Song Group=Song Group
 Song Options=Song Options
 SongsPerPlay=Songs Per\nPlay
+Sort=Sort
 Sound Options=Sound Options
 SoundResampleQuality=Resampling\nQuality
 SoundVolume=Sound\nVolume