Create and enable a swapfile for devices with USB support. It is assumed that extra USB storage is already configured via opkg and fstab, as the swapfile most likely won't fit into the MTD storage.
- boot: if swapfile service is enabled, mounts the swapfile on boot and logs the action on syslog;
- start: mounts the swapfile on demand, logs the action on syslog and displays a message on the console;
- stop: stops the swapfile, logs the action on syslog and displays a message on the console;
- restart: stops and restarts the swapfile, logs both actions on syslog and displays a message on the console;
- create: if there is no swap memory already in use, it creates a swapfile which has the same size as the device's RAM and enables it to run at boot time;
- status: checks the status of the swapfile, and is capable of detecting if swap memory is alredy present;
- enable: enables the swapfile service, so it WILL run at boot time;
- disable: disables the swapfile service, so it WILL NOT run at boot time;