Add --prettify option, to reformat a script (losing comments).

Since our syntax extensions transform the source at parse time, all syntax extensions are disabled. The optimizations are disabled too, as it doesn't make sense to prettify and optimize at the same time (the optimizer would remove the constants that we're trying to keep).

Addresses #4 in a more user-friendly way.

main.py

@@ -217,6 +217,7 @@ Usage: {progname}
     [--avname=<name>]         * specify name of avatar saving the script
     [--assetid=<UUID>]        * specify the asset UUID of the script
     [--shortname=<name>]      * specify the script's short file name
+    [--prettify]                Prettify source file. Disables all -O options.
     filename                    input file
 
 Options marked with * are used to define the preprocessor macros __AGENTID__,
@@ -359,6 +360,7 @@ validoptions = frozenset(('extendedglobalexpr','breakcont','extendedtypecast',
     # undocumented
     'lso','expr','rsrclimit',
     # 'clear' is handled as a special case
+    # 'prettify' is internal, as it's a user flag
 ))
 
 def main(argv):
@@ -382,7 +384,7 @@ def main(argv):
     try:
         opts, args = getopt.gnu_getopt(argv[1:], 'hO:o:p:P:HTyb:L:',
             ('optimizer-options=', 'help', 'version', 'output=', 'header',
-            'timestamp','python-exceptions',
+            'timestamp', 'python-exceptions', 'prettify',
             'preproc=', 'precmd=', 'prearg=', 'prenodef', 'preshow',
             'avid=', 'avname=', 'assetid=', 'shortname=', 'builtins='
             'libdata='))
@@ -404,6 +406,7 @@ def main(argv):
     mcpp_mode = False
     preshow = False
     raise_exception = False
+    prettify = False
     builtins = None
     libdata = None
 
@@ -525,8 +528,15 @@ def main(argv):
 
         elif opt == '--shortname':
             shortname = arg
+
+        elif opt == '--prettify':
+            prettify = True
     del opts
 
+    if prettify:
+        options &= set(('rsrclimit',))
+        options.add('prettify')
+
     try:
 
         if 'rsrclimit' in options: