add rules for metaphlan2 heatmap

tools/metaphlan2/metaphlan2_heatmap/config.yaml

+samples:
+  - S1
+  - S2
+input: data/table.txt
+
+metaphlan2_merge:
+  options: ""
+  exec_command: metaphlan_hclust_heatmap.py
\ No newline at end of file

tools/metaphlan2/metaphlan2_heatmap/metaphlan2_heatmap.rules

+__metaphlan2_heatmap_exec_command = config['metaphlan2_heatmap']['exec_command']
+__metaphlan2_heatmap_options = config['metaphlan2_heatmap'].get('options', "")
+
+rule heatmap:
+    input:
+        __metaphlan2_heatmap_input
+    output:
+        __metaphlan2_heatmap_output
+    params:
+        exec_command = __metaphlan2_heatmap_exec_command,
+        options = __metaphlan2_heatmap_options
+    shell:
+        "{params.exec_command} {params.options} --in {input} --out {output}"

tools/metaphlan2/metaphlan2_heatmap/usage_example.rules

+"""
+This example would be used as followed:
+
+$ snakemake --snakefile metaphlan2_heatmap.rules
+
+It requires the presence of input files within data/table.txt to work based on config file
+"""
+
+configfile: "config.yaml"
+
+__input = config['input']
+__main_output_dir = config.get('output_dir', 'output')
+
+# ---- Metaphlan2 heatmap
+__metaphlan2_heatmap_output_dir = __main_output_dir + "/metaphlan2_heatmap"
+__metaphlan2_heatmap_output_file_name = config['metaphlan2_heatmap'].get('output_name',"heatmap.png")
+__metaphlan2_heatmap_input = __input
+__metaphlan2_heatmap_output = "{dir}/{file_name}".format(dir=__metaphlan2_heatmap_output_dir,
+                                                         file_name=__metaphlan2_heatmap_output_file_name) 
+include: "metaphlan2_heatmap.rules"
+
+rule all:
+    input:
+        __metaphlan2_heatmap_output