select_series: Select Series from Metadata File
In treenet/treenetproc: Clean, Process and Visualize Dendrometer Data

select_series selects series from the metadata file based on selection criteria specified by the user (i.e. site, sensor_class, etc.). In addition, reference temperature data is selected for all dendrometer series.

1	select_series(site, sensor_class, sensor_name, path_cred)

`site`	character, specify the site. String is not case sensitive.
`sensor_class`	character, specify a single or multiple sensor classes. String does not have to contain the full name of the sensor class, i.e. `"dendro"` works for `"dendrometer"`. String is not case sensitive.
`sensor_name`	character, specify the name of a single or multiple sensors (e.g. `"LWF-Demo-1.dendrometer.ch0"`).
`path_cred`	optional argument to specify the full path to the file `config.yml` containing the database login data. File can also be copied to the main folder of the package for automatic recognition.