include environment in INFO file of runs
remove 'kind' attribute from datasets
add database update script to convert 'experiment-kind' to 'experiment_kind'
bump version
use pickle for serialization of all data and add INDEX file

pyyaml performance was way too bad for medium sized datasets.
[simdb.run] ensure SIMDB_PATH exists
[simdb.run] add convenience method add_logfile()
[run] strip PS1 from env

The PS1 may contain strange formatting characters and probably does not add
much information anyway...