Add an initial and basic log test.
Rename block number to block index to avoid confusion with the block
number field of the header.
Make the log file handler a member of the Log class. Avoids having
to open the file each time a block is to be read.
Allow for non-indexed blocks (blocks forming the log header) to be
read.
Allow a cursor to read directly from a string buffer.
Add support for parsing the header blocks of InnoDB log files.
Cleanup and rename LogBlock header/trailer offset constants.
Initial IO tracing support for Innodb::LogBlock.
Add the flush bit to the header of a LogBlock.
Remove placeholder (and broken) log record content reading. Content
was being read over other fields.
Log records of type MULTI_REC_END and DUMMY_RECORD have no other
content besides their type field.
Rename (and rework) LogBlock::record to first_record_preamble as to
better reflect its functionality.
Merge pull request #18 from darnaut/log-support-work

Support for parsing the header blocks of InnoDB log files and other fixes and cleanups.