query_extract: Query an aggregated dataframe to subset requested channels
In maximemeylan/Excyte: Exhaustive eXploration of CYTometry data

Query an aggregated dataframe to subset requested channels

1	query_extract(processed_fcs_obj, channels = c("all", "with_desc")[1])

`processed_fcs_obj`	list containing a datraframe of processed intensities for each event and informations of channel used
`channels`	vector containing channels to select. Can be "all" to select all channels, "with_desc" to select channels with a marker description or a vector a channels.