Add a test to make sure we can iterator with any list of entities.
- Added more unit tests
- Heavily altered iterators as a result.
- Added more unit tests
- Heavily altered iterators as a result.
Interator performance enhancement and correctness.
Seperated entity and component interation in search for performance on in visual studio
Result:  Improved sparse and dense perf, reduce saturated perf.
Try simpler iteration (no fold)
Back to fold method, seems to be the best on average.
Large refactoring of iteration mechanisms.
Fix clang compilation error
Fix old gcc compile error
Upgrade libc for clocks support.
Try eglibc
Try eglibc
Merge branch 'iterator_cleanup' of git@github.com:cdglove/entity.git into iterator_cleanup

Conflicts:
	.travis.yml
Try newer libc6
Remove -bin
Remove -i686
Try plain libc6
Add rt to linker flags
Try no-as-needed