modified docs

See merge request toar/mlair!248

Resolve "new dependencies occured"

See merge request toar/mlair!246

Resolve "add box-cox transformation to default data handler and statistics"

See merge request toar/mlair!241

update #275 branch

See merge request toar/mlair!245

Merge branch 'lukas_issue278_bug_mse-monitoring-plot-not-working-with-multiple-branches' into 'develop'

Resolve "BUG: mse monitoring plot not working with multiple branches"

See merge request toar/mlair!243

Resolve "BUG: loading of custom objects not working"

See merge request toar/mlair!242

removed unnecessary changes from previous commits, there is now a new method for the keras magic to emphasise its importance

first fix to make training resumption possible, but this will slow down the training by 5-10s per epoch (if model improves)

Resolve "BUG: change of internal and external climatology"

See merge request toar/mlair!240

create now forecasts for internal (train, val) and external (test) data, updated skill score calculation, case IV is still under construction

Resolve "add min max scaling for default data handler and statistics"

See merge request toar/mlair!239

Resolve "individual transformation"

See merge request toar/mlair!237

new method required for all data handlers to decouple from postprocessing run module: apply_transformation

transformation is set to empty dict instead of None, added defaults section to docs, needs to be filled in future

Resolve "release MLAir Logo"

See merge request toar/mlair!238