Based on heap profiling, buffers used for storing half-parsed fields are
a major contributor to the overall memory consumption of reads. This
memory was completely "under the radar" before. Track it by using
tracked `temporary_buffer` instances everywhere in
`continuous_data_consumer`. As `continuous_data_consumer` is the basis
for parsing all index and data files, adding the tracing here
automatically covers all data, index and promoted index parsing.
I'm almost convinced that there is a better place to store the `permit`
then the three places now, but so far I was unable to completely
decipher the our data/index file parsing class hierarchy.
1. Move tests to test (using singular seems to be a convention
in the rest of the code base)
2. Move boost tests to test/boost, other
(non-boost) unit tests to test/unit, tests which are
expected to be run manually to test/manual.
Update configure.py and test.py with new paths to tests.
