Updating composer to allow installs on laravel 5.2

Updating the composer requirements to allow installs on Laravel 5.2

Fixing a bug if storage path is not common across servers

The storage path was used by the command to generate the mutexPath() value, which may not be common across servers (or, more specifically, two copies on the same server). This removes the storage path from the generation to identify the command.

More robust parallel execution tests

Storing the completion time in the database and keeping the lock for 10 seconds after the completion time to prevent a server from catching a lock on a short-running process.

Strict standards fix

Fixing issues with strict standards. Also applying the license info.

Initial Release

Initial release of the MultiServerEvent package.