Disabled SingleThreadedEngine and enabled MultiThreadedEngine
fix for MultiThreadedEngine destructor
introduced recursive lock for Table
switched ptr mutex to recursive_mutex
fix for ptr desctructor
Fixed GCC 4.8 issues in this branch
Merge branch 'master' into multithreading

Conflicts:
	global/Ptr.h
	mains/benchmark.cpp
	mains/server.cpp
Merge branch 'master' into multithreading

Conflicts:
	mains/benchmark.cpp
Added more detailed error message for invalid task states
enabled SingleThreadedEngine for benchmarking
increased number of benchmark runs to 10
cleaned up make file a bit
fixed tests for MultithreadedEnging
fixed for multihreaded engine
Merge branch 'master' into multithreading

Conflicts:
	global/const.h
	mains/benchmark.cpp
	storage/AbstractTable.cpp
fixed compiler warnings in Makefile
enabled test suite for single and multithreaded tests
introduced taskID as unique task identifier
remouved unsued arguments warning
remouved unsued arguments warning