Blazegraph 2.1.5 Release Candidate

Release Notes - Blazegraph (by SYSTAP) - Version BLAZEGRAPH_2_1_5

** Bug
    * [BLZG-2066] - AssertionError in path query with MINUS
    * [BLZG-2079] - Wrong results for fully constrained "+" property path 
    * [BLZG-2082] - one-argument substr produces NPE when combined with GROUP By
    * [BLZG-2083] - str() produces NotMaterializedException when using group by/sample
    * [BLZG-2084] - Bad join ordering with nested values clause
    * [BLZG-2089] - Bad performance with path queries in 2.1.4
    * [BLZG-2090] - NPE in com.bigdata.rdf.graph.analytics.SSSP service
    * [BLZG-2091] - Regression: IF + BOUND produce exception in 2.1.4
    * [BLZG-2097] - Service clause breaks query performance
    * [BLZG-2098] - Using query as subquery leads to NotMaterializedException
    * [BLZG-3644] - StackOverflowError in 2.1.4
    * [BLZG-4244] - fix NSS_PROPERTIES handling in the debian version of loadRestAPI.sh
    * [BLZG-4245] - Add code to allow customization of search endpoint types.
    * [BLZG-4246] - Debian README.md formatting
    * [BLZG-4247] - Wiki Data -> Wikidata
    * [BLZG-4248] - Configuration option enableRawRecordsSupport
    * [BLZG-4249] - SUBSTR with starting location less than 1
    * [BLZG-4323] - hint:runFirst not considered for Subqueries and Named Subquery Includes
    * [BLZG-4403] - Blazegraph Export Option in UI
    * [BLZG-4476] - DISTINCT does not eliminate duplicate rows
    * [BLZG-5590] - Negated path produces exception
    * [BLZG-5736] - Strings with quotes are not properly encoded in federated queries
    * [BLZG-7794] - Need a way to ensure POST request is read-only
    * [BLZG-8852] - Blazegraph colt component has same jar name as another library
    * [BLZG-8864] - Namespace creation vulnerable to XSS injection
    * [BLZG-8865] - Sitewide Lack of Clickjacking Protection
    * [BLZG-8937] - Reordering Values Clauses
    * [BLZG-8963] - Async Channel Used for Blobs is not closed
    * [BLZG-8986] - Provide Jetty SSL Configuration Example
    * [BLZG-8999] - REGEX() is not affected by timeout
    * [BLZG-9000] - Unsupported Operation Exception When Forwarding Key Set
    * [BLZG-9153] - Add Aduna BSD-Style License to LEGAL
    * [BLZG-9154] - Surefire plugin needs fix for Java8
    * [BLZG-9155] - SERVICE SILENT still produces an error 
    * [BLZG-9157] - SPARQL Update produces "BigdataValue not available" exception on integers
    * [BLZG-9159] - PipelinedHashIndexAndSolutionSetJoinOp messes up SERVICE + MINUS


** Improvement
    * [BLZG-2078] - Make search endpoint type customizable
    * [BLZG-2092] - Make SailBase connection timeout configurable
    * [BLZG-7825] - Remove dependency to obsolete concurrent library
    * [BLZG-8850] - Please upgrade Jetty version to 9.2.9+ to avoid HttpParse Memory Error 
    * [BLZG-9001] - Provide Jetty Authentication Configuration Example
    * [BLZG-9003] - Add timeout for query parsing phase
    * [BLZG-9087] - Document CSRF Mitigation
    * [BLZG-9156] - Add support for regex q option
    * [BLZG-9158] - Upgrade jetty to 9.4.x
    * [BLZG-9161] - Add counter for running queries
    * [BLZG-9162] - Add capability to refuse new requests if executor service is overloaded.