Revert "Merge pull request #3 from Motiejus/system_memory"

This reverts commit a9dc760ab2658cd00f8e7eba9c3b00a322083881, reversing
changes made to 91e2cca48de1e81d8a85d069c320439cc11082ba.

I misread the documentation
CHANGE disable used_fds stats
OPT code cleanup and more efficient, start with unit testing
CHANGE 100percent unit coverage on estatsd + optimized simple increments
Merge branch 'cleanup_and_testing'