Update README to include gzip support for fasta files

Added support for gzip compressed fasta files in usage instructions.

Author: cjain7

README.md

@@ -25,7 +25,7 @@ $ ./fastANI -h
 $ ./fastANI -q [QUERY_GENOME] -r [REFERENCE_GENOME] -o [OUTPUT_FILE] 
 ```
 
-Here QUERY\_GENOME and REFERENCE\_GENOME are the query genome assemblies in fasta or multi-fasta format.
+Here QUERY\_GENOME and REFERENCE\_GENOME are the query genome assemblies in fasta or multi-fasta format. A gzip'd compressed fasta file is also acceptable.
 
 * **One to Many.** Compute ANI between single query genome and multiple reference genomes: