Implement a new log file format

Change from v0
- 4 byte uint path length
- 4 byte uint data length
- 8 byte uint timestamp
- path
- data
to v1:
- 1 byte record separator (0x1e)
- 2 byte uint path length
- 4 byte uint data length
- 8 byte uint timestamp
- path
- data
With this format, we can recover from a corrupted record in the file by seeking
to the next record separator.
Add a generator for reading log files.
Add util code for converting V0 logs to V1.
Read logs using the generator from util.files
Update to use the common log reading code.
Fix imports for conversion utility
Merge pull request #5 from mreid-moz/log_file_v1

Implement a new log file format