[SNEAKER-33] Design decorator pattern
Merge branch 'dev' of github.com:yanzhengli/sneaker into dev

Conflicts:
	include/functional/decorators.h
	tests/functional/decorators_unittest.cc
Updated Makefile
[SNEAKER-44] Improve `fixed_time_interval_daemon_service` to prevent segfault from happening
[SNEAKER-45] Implement Tarjan's Strongly Connected Graph Algorithm
[SNEAKER-46] Update README.md to include more elaborate project description
[SNEAKER-47] Have `make` build binary instead of `make all`
Version 0.2.3