Alpha release

Objective:

• simpler and more coherent code base
• remove unnecessary dependency of all objects on an Experiment instance
• clearer API to avoid potential user mistakes

Main changes:

• deleted Experiment object (replaced by optional Container)
• plotters can be instantiated without an experiment
• each metric holds its own history
• new Config object
• use of state_dict objects to dump and load data
• manual mode for plotting: data is only sent when user decides (-> significant performance gains for frequent updates)

v0.3: Merge pull request #10 from oval-group/visdom

• New syntax to manipulate metrics and values
• Introduction of BestMetric
• More flexibility when plotting on visdom
• Data is cached when connection to visdom is lost, and sent again when connection is recovered
• Possibility to save stdout to a file

v0.2

• Compatibility python 2 and 3
• Float casting in metrics updates