MemoryFree.h

When I try to use this version, I get...

```
....../libraries/GSM/MemoryFree.cpp:6:25: error: MemoryFree.h: No such file or directory
```

The standard installed copy doesn't even have MemoryFree.cpp, so wondering what version this is.

Is there a commit/tag that corresponds to the "official" version?
