Make Unicode some strings that should be, and improve error reporting in builtins.txt

Also work towards the convention that strings that represent text (possibly translatable) are in double quotes, not single.

main.py

@@ -38,9 +38,9 @@ def ReportError(script, e):
     sys.stderr.write(e[0] + '\n')
 
 class UniConvScript(object):
-    '''Converts the script to Unicode, setting the properties required by
+    """Converts the script to Unicode, setting the properties required by
     EParse to report a meaningful error position.
-    '''
+    """
     def __init__(self, script):
         self.script = script
 
@@ -50,7 +50,7 @@ class UniConvScript(object):
                 self.script = self.script.decode('utf8')
             except UnicodeDecodeError as e:
                 self.errorpos = e.start
-                raise EParse(self, 'Invalid UTF-8 in script')
+                raise EParse(self, u"Invalid UTF-8 in script")
         return self.script
 
 def PreparePreproc(script):
@@ -155,7 +155,7 @@ def ScriptHeader(script, avname):
 def Usage(about = None):
     if about is None:
         sys.stderr.write(
-r'''LSL optimizer v{version}
+ur"""LSL optimizer v{version}
 
     (C) Copyright 2015 Sei Lisa. All rights reserved.
 
@@ -199,12 +199,12 @@ Preprocessor modes:
 Normally, running the preprocessor needs the option 'processpre' active, to
 make the output readable by the optimizer. This option is active by default.
 
-'''.format(progname=sys.argv[0], version=VERSION))
+""".format(progname=sys.argv[0], version=VERSION))
         return
 
     if about == 'optimizer-options':
         sys.stderr.write(
-r'''
+ur"""
 Optimizer control options.
 + means active by default, - means inactive by default.
 Case insensitive.
@@ -295,11 +295,11 @@ Case insensitive.
                        is useless with 'optimize' and 'optsigns', and is of
                        basically no use in general, other than to see where
                        automatic casts happen.
-''')
+""")
         return
 
 def main():
-    '''Main executable.'''
+    """Main executable."""
 
     # If it's good to append the basename to it, it's good to append the
     # auxiliary files' names to it, which should be located where this file is.