Add query parser encoding option

Hi, needed UTF-8 support and noticed that the bundle doesn't have an option to set ZendSearch QueryParser encoding, which was the only way i could get it to work properly. Tried a different analyzer but it didn't work, i had problems related to iconv. 
I've made some changes to your bundle to accept a new configuration parameter called query_parser_encoding to set the query parser encoding.

Great tool for those who need to use lucene by the way!!!
IMO, this check should be removed because if we get an index with a custom encoding and then get an other index with the default encoding, the custom encoding will be used for the second index.