The Timer::restart() method now resets the elapsed time properly.

This completes Issue #10.
NotificationCenter destructor no longer throws a NotificationError when observers are still registered.

Fixes Issue #11.
Removed the sha1.h file from being installed into the include directory.

The entire smallsha1 library needs to be hidden from Bump users. This header should not be installed. Instead, users should only use the CryptographicHash wrapper class.

Fixes Issue #14.
The NotificationCenter now uses unique and shared locks where necessary to avoid deadlock conditions.

Fixes Issue #13.
Incremented the version number to 1.1.5.