With default_flow_style = False, yaml.dump writes lists with an element
per-line, (with -), what makes the output very long and not very
readable. Method flowStyleLists makes uuids and covariances list
flow-styled, i.e. [x, y, z, ...]
Add a decimal point to exponential formated floats; if not, get loaded
as strings, due to a bug in pyyaml. See this ticket for details:
http://pyyaml.org/ticket/359
Make a bit more interesting database