Introduce type RawIdent; only 9 imports of Data.ByteString.Char8 remain

The fact that identifiers are represented as ByteStrings is now an internal
implentation detail in module GF.Infra.Ident. Conversion between ByteString
and identifiers is only needed in the lexer and the Binary instances.

src/compiler/GF/Compile/GrammarToPGF.hs

@@ -30,7 +30,6 @@ import Data.Char (isDigit,isSpace)
 import qualified Data.Set as Set
 import qualified Data.Map as Map
 import qualified Data.IntMap as IntMap
-import qualified Data.ByteString.Char8 as BS
 import Data.Array.IArray
 import Text.PrettyPrint
 import Control.Monad.Identity
@@ -250,8 +249,7 @@ genCncFuns gr am cm seqs0 cdefs fid_cnt cnccats =
             ctxt = mapM (mkCtxt lindefs) hargs_C
             fids = map (mkFId arg_C) fid0s
 
-    mkLinDefId id = 
-      identC (BS.append (BS.pack "lindef ") (ident2bs id))
+    mkLinDefId id = prefixIdent "lindef " id
 
     toLinDef res offs lindefs (Production fid0 funid0 _) =
       IntMap.insertWith (++) fid [offs+funid0] lindefs