v0.13.0 - Large release, lots of new features

This version introduces a lot of great changes including rich metadata of experiments like descriptions, comments and tags, Metrics as value and meta containers and also descriptions of computing those values, links between objects, file and model artifacts, slugs for models as well as lots of other improvements.

Adds

• CLI #195 #198 #224 #228
  Cascade now introduces command line interface. The first version is simple and
  allows to use viewers, comment, tag and describe objects, view meta.
• #208 #217 #223
  Metrics are new entity that helps to organize metric values, build metadata around simple numerical values
• #210 #211 #229
• Models now have unique slugs #192 #199
• Models can log state, metrics without saving #200
• Comments for objects #202
• Descriptions of objects #196
• Tags for objects #197 #203
• Artifacts are now separated from wrapper #193
• File artifacts can be attached to the model #194

Enhances

• #201
• #204
• #206
• #207
• #209 #221
• #212
• #213
• #214
• #215 #225 #227
• #216
• #226
• #230

Fixes

• #205

Removes

• #191

Breaking changes

• Metrics are now stored differently, this is what can be fixed by new migrate CLI command #210 #211 #229
• History logs are now stored as deltas and would not be compatible with old ones #215 #225 #227
• meta_prefix was removed from constructors and update_meta no longer accepts path to files, to migrate use links