SES-1652 first steps for transaction handling over http.
SES-1652 added location header, put more advanced concurrency handling
in place for registry.
SES-1652 changed ActiveTransactionRegistry to singleton, using slightly
more sophisticated locking/synchronization strategy.
SES-1652 start of functionality at the client side
SES-1652 using action parameter to indicate whether operation is a read,
add, or delete.
SES-1652 added handling of SPARQL in transactions and getStatements,
both client- and server-side.
IN-1331 fixed spring bean mappings, modified begin()
IN-1331 removed unused imports, made test.teardown stop server in
failsafe way.
SES-1652 ongoing
SES-1652 added dependency on rio-binary to httprepository
Merge branch '2.8.x' into ses-1652

Conflicts:
	compliance/store/src/test/java/org/openrdf/repository/http/HTTPStoreConnectionTest.java
	core/repository/http/src/main/java/org/openrdf/repository/http/HTTPRepositoryConnection.java
minor fix in problem caused by merge
SES-1652 bumped protocol version to 7.
SES-1652 various fixes in concurrency handling.
SES-1652 simplified transactionregistry to use single map for both
connection and locking mechanism. Using Guava Cache with time-based
expiry to close stale transactions (currently set to 60 seconds fixed)
SES-1652 direct adds/removes now immediately flushed to statement
add/remove REST resource instead of converted to transaction.
SES-1652 operations on namespaces are not part of transaction.
SES-1652 ongoing fixes
SES-1652 parser config / statement removal fixed. all compliance tests
on HTTPRepositoryConnection now greenline.
SES-1652 using enum-as-singleton pattern.