remove some redundant imports of GF.Text.UTF8

src/GF/Compile/Export.hs

@@ -17,7 +17,6 @@ import GF.Speech.SRG
 import GF.Speech.VoiceXML
 import GF.Speech.SLF
 import GF.Speech.PrRegExp
-import GF.Text.UTF8
 
 import Data.Maybe
 import System.FilePath

src/GF/Compile/GrammarToGFCC.hs

@@ -23,7 +23,6 @@ import qualified GF.Infra.Option as O
 import GF.Infra.Ident
 import GF.Infra.Option
 import GF.Data.Operations
-import GF.Text.UTF8
 
 import Data.List
 import Data.Char (isDigit,isSpace)

src/GF/Compile/PGFPretty.hs

@@ -7,7 +7,6 @@ import PGF.Data
 import PGF.Macros
 
 import GF.Data.Operations
-import GF.Text.UTF8
 
 import Data.Map (Map)
 import qualified Data.Map as Map