Merge pull request #37 from starschema/engine-refactor

Fixed compile error.
add logs to engine lib
add more logs and fix
eliminate util.hh confusion; add fault injector
improve variable names in fault injector; add more tests too
Merge pull request #38 from starschema/fault-injection

Fault injection
replacing non-functional std::async
fix Linux build error
more logs and error handling
Merge branch 'master' of https://github.com/starschema/virtdb-common
restructure engine code
asking for resend when we detect missing blocks
change order of mark_as_received
administer received chunks in chunk_store
remove compiler warning
removing next_chunks map, because of infrequent errors
fix silly bug
Merge remote-tracking branch 'origin' into engine-refactor

Conflicts:
	common.gyp
	engine/chunk_store.cc
	engine/column_chunk.hh
	engine/data_chunk.cc
	test/gtest_main.cc