Fix some typos and convert windows-installer scripts to Python 3

The scripts are poorly converted as Windows is not really supoported
anymore and would need some love from a contributor who actually uses
Windows

src/diffuse/main.py

@@ -534,8 +534,7 @@ class Diffuse(Gtk.Window):
                 info.name, info.encoding, info.revision, info.label = name, encoding, None, label
                 info.last_stat = info.stat = os.stat(name)
                 self.setFileInfo(f, info)
-                # update the syntax highlighting incase we changed the file
-                # extension
+                # update the syntax highlighting in case we changed the file extension
                 syntax = theResources.guessSyntaxForFile(name, ss)
                 if syntax is not None:
                     self.setSyntax(syntax)

windows-installer/build.py

@@ -46,7 +46,7 @@ def copyFile(src, dest, use_text_mode=False,enc=None):
     s = f.read()
     f.close()
     if enc is not None:
-        s = codecs.encode(unicode(s, 'utf_8'), enc)
+        s = codecs.encode(str(s, encoding='utf_8'), enc)
     f = open(dest, w)
     f.write(s)
     f.close()
@@ -190,12 +190,12 @@ for lang in os.listdir(d):
         while True:
             i = s.find('&#', idx)
             if i < 0:
-                a.append(unicode(s[idx:], 'latin_1'))
+                a.append(str(s[idx:], encoding='latin_1'))
                 break
-            a.append(unicode(s[idx:i], 'latin_1'))
+            a.append(str(s[idx:i], encoding='latin_1'))
             i += 2
             j = s.find(';', i)
-            a.append(unichr(int(s[i:j])))
+            a.append(chr(int(s[i:j])))
             idx = j + 1
         s = ''.join(a)
         s = codecs.encode(s, 'utf-8')

windows-installer/setup.new.py

@@ -196,7 +196,7 @@ def copyFile(src, dest, use_text_mode=False,enc=None):
     s = f.read()
     f.close()
     if enc is not None:
-        s = codecs.encode(unicode(s, 'utf_8'), enc)
+        s = codecs.encode(str(s, encoding='utf_8'), enc)
     f = open(dest, w)
     f.write(s)
     f.close()