GridLocate: Set default pa variant to 1; allow 0 for aggressiveness to stand for default value, currently 1.0 but possibly specific to type of perceptron
Perceptron: Map labels differently so that aggressiveness = 1.0 means what it should mean
print: Separate fixme_error and unsupported
io: Add std_file_handler for stdin/stdout/stderr
FeatureVector: get_csv_labeled_instances: Use an Iterator rather than Source
ClassifyApp: New stand-alone app in package learning for testing perceptrons
Pull out gridlocate debug code into general util.debug so other apps can use it
Classifier: Add sorted_scores
ClassifyApp: Fix so correct/wrong is output and final accuracy; get debug working
Perceptron: Compute, output num errors, adjustments (not always same)