Consolidated target lists for aliases.
SConstruct now builds a useful directory structure allowing more shared state.  Once the data_directory is populated with the data and script links, they can be reused.  Moreover, for each seed used in a build, a new directory is created to hold all of the initial training sets and derived models, so they need only be created once per seed.
The proportion of the data to go to the training set is now a parameter, set by default to .99.