Reduced memory used and add option to skip notes

[ecamacho]

1. Use an autoreleasepool to deallocate promptly the content of a log after is tokenised
2. Add an --omit_notes option to the parse command to address https://github.com/spotify/XCLogParser/issues/108

With the autoreleasepool the memory is deallocated faster, according to Instruments:

Before:

---

After

---