add json validation + typo fixes in config.m4
Add json extension dependency
gitignore
remove srand initialization from RINIT
All *Response classes, SolrDocument, SolrInputDocument are now final
All parameters functions throws SolrIllegalArgumentException instead of E_RROR
All SolrClient methods throws SolrClientExceptions instead of E_WARNING + SolrClientException

SolrClientExceptions are now more informative
Feature: Added SolrClient::system method to retrieve Solr Server System Info