build_graph: Builds a graph from a data.frame of nodes
In ParkerICI/scgraphs: Analyzing single-cell data using graphs

Builds a graph from a data.frame of nodes

1	build_graph(tab, col.names, filtering_T = 0.8)

`tab`	A `data.frame` of graph nodes. All the columns of `tab` will become vertex properties of the output graph
`col.names`	A character vector indicating which columns of `tab` should be used to calculate distances
`filtering_T`	The threshold used to filter edges in the graph. If this value is `< 1` the edges are filtered based on the cosine similarity value. If this is an integer `>= 1` they are filtered based on rank for each node (i.e. for each node only the edges with rank less than the threshold are retained)