Further refactoring

This should finish the work to make all globals to local variables.
That allows LuaJIT to properly compile things by interning the
references to the relevant parts (rather than looking up globals
all the time which stops a trace).

frontend/document/credocument.lua

@@ -2,6 +2,8 @@ local Geom = require("ui/geometry")
 local CreOptions = require("ui/data/creoptions")
 local Document = require("document/document")
 local Configurable = require("ui/reader/configurable")
+local Font = require("ui/font")
+local Screen = require("ui/screen")
 -- TBD: DrawContext
 
 local CreDocument = Document:new{
@@ -22,7 +24,7 @@ local CreDocument = Document:new{
 }
 
 -- NuPogodi, 20.05.12: inspect the zipfile content
-function CreDocument:zipContentExt(fname)
+function CreDocument.zipContentExt(self, fname)
 	local outfile = "./data/zip_content"
 	local s = ""
 	os.execute("unzip ".."-l \""..fname.."\" > "..outfile)