Catch SIGTERM also and don't print when signal handling

To prevent any undefined behaviour from happening

Handle SIGINT gracefully

Also change -p <path> to simply <path> as positional argument

Add error handling within loop

Application should no longer die if there is error within the loop to handle file triggers, unless it's due to panic.

Trigger shell template command execution

Able to watch for file and directories via glob patterns, and trigger shell template command execution with substitution of "{path}" and "{event}".