features: rework feature test macros
cmake: added optional hardening support
cmake: additional compiler warnings
stress: make local functions static
blob: make local functions static
cmake: added sanitizers

Can be used in Clang >= 3.0 and gcc >= 4.8
cmake: added modeline

Also cleaned up commented code
cache: use memmove for overlpping ranges
Merge pull request #18 from SaveTheRbtz/master

Stability, build improvements and sanitizers.