todo make_brian_group
merge
loaddb last by default (option load_all=False)
plot_period_histogram improvements
removed problem in coreelation index function where the firing_rate function was overwritten by a variable when normalize=True
Merge remote-tracking branch 'mrk/master'
added a dumpdb version where columns containing numpy data are stored as seperate tables. It works fine but the current version seems to verry unperformant (100x slower then pickle) gitg
updated the numpy dumpdb version to use variable length arrays instead of one array per column entry but pickel is still faster by a factor of 1.5 or so
removed bug with multiple numpy columns and only check if the first item in a column is a numpy array to decide wheater to store them seperatly
removed a bug in loaddb where the store was not closed if load_all = False
Implemented numpy flavor loaddb for load_all=true only
some refinements and the start of numpy dump for load_all=True