Multi-commit:

- Fix a bunch of bugs found during the debut of the LSL calculator.
- Add infrastructure for functions to be able to produce a result or not depending on arguments. Fixes the llBase64ToInteger/llXorBase64/llXorBase64StringsCorrect cases where they are not deterministic, and allows for the addition of some extra functions whose value can be determined in some cases (e.g. llDetectedType(-1) is always 0). Added several such functions in a new module.
- Add the constant folding option to the help and the default options.

lslopt/lslparse.py

@@ -1754,8 +1754,9 @@ class parser(object):
                     # No location info but none is necessary for forward
                     # declarations.
                     ret[name] = {'Kind':'v','Type':typ,'Scope':0}
-
                     while self.tok[0] != ';': # Don't stop to analyze what's before the ending ';'
+                        if self.tok[0] == 'EOF':
+                            return ret
                         self.NextToken()
                     self.NextToken()
         except EParseUEOF: