Now takes a structure that, if present, enables the query
classification caching and specifies the properties of the
cache.
For the time being no actual properties are yet available.
The canonicalization process now strips non-executable comments from the
SQL and replaces all constants in executable comments.
Enabled the comment test and updated expected output of the select and
alter tests.
Updated tests with new expected output. Also took new function into use
and removed the old one.
Since the comment removal isn't added yet, one of the tests is expected to
fail and it is temporarily disabled.
Cleaned up and updated the test; the code was written with a pre-C99
standard in mind.
Added a get() method into mxs::Buffer to make it easier to use with
non-C++ functions.
