Added options to the Smarty extension that configure the text that is used to replace quotes. This makes it possible to use the correct quotes in languages other than English.
Replaced smart_lsquo etc. by a single option smart_substitutions which allows to overwrite all substitution strings. Fixed line length in docs.
Fixed an old typo in the smarty extension and added a test case.
Added test for the new 'smart_substitutions' feature of Smarty extension.
Renamed 'smart_substitutions' option to 'substitutions'. Fixed a typo.