Implement a tool for ad-hoc computations

[dcesari]

Currently the alchimia module, although powerful and generic, is limited to pointwise computations in metadata space, where variable is the only varying metadatum.
There is the need for ad-hoc computations, e.g. the wind direction at which the maximum in time of wind intensity occurs, or thermodynamic computations involving vertical profiles, which require a specialised tool. A template has been drafted in v7d_column.

[dcesari]

Other request: temperatura lungo la linea adiabatica satura a partire dal lifted condensation level