plot_TIPC_heatmap_overlayDens: Heat-map of TIPC metric color-coded by clustering results
In MPE-Lab/TIPC: Tumor-Immune Partitioning and Clustering (test)

Plotting heat-maps of TIPC metric clustering results of all k's unless it is specified; using R package Heatmap

plot_TIPC_heatmap_overlayDens(
  root_dir = NULL,
  one_k = NULL,
  clustering_subfolder_nm = NULL,
  density_data = NULL
)

`root_dir`	A directory path containing (1) the TIPC_metrics, i.e. normalized TIPC metrics of all 5 directions output from `normalize_metrics`; (2) the result folder of TIPC clustering results output from `consensus_clustering`.
`one_k`	An integer specifying the cluster number selected for heat-map plotting; otherwise all k's found under `TIPC_cluster_dir` will be processed.
`clustering_subfolder_nm`	A character string of sub-folder name generated during `consensus_clustering`, parked under `root_dir`.
`density_data`	A data.frame containing the tumor-level density data of no. of rows equals to no. of cases/tumors (tumor_ids in row.names), each column represents the density values of a specific cell-type.