according to http://www.jsonrpc.org/specification#error_object the error code for parse error is -32700
catch exception when parsing malformed JSON and set property
check for parse error property on request
added test case, formatting
comment added
fixed ErrorTest.php and put real value for parse error
Merge pull request #4818 from tylkomat/issue4817

Issue4817
Merge branch 'hotfix/4818'

Close #4818
Fixes #4817