Update README.md

Author: WenchaoLin

README.md

@@ -10,11 +10,11 @@ Usage
 Usage: GCcalc.py -f input.fa [-w 1000] [-s 1000]
 
 Options:
-				-h, --help            show this help message and exit
+    -h, --help  show this help message and exit
 
-				-f FASTA, --file=FASTA
-                        Input Fasta format file
-  			-w WINDOWSIZE, --window=WINDOWSIZE
-                        default:1000 WindowSize to calculate
-  			-s STEPSIZE, --step=STEPSIZE
-                        default:1000 StepSize for slide widows
+    -f FASTA, --file=FASTA
+        Input Fasta format file
+    -w WINDOWSIZE, --window=WINDOWSIZE
+        default:1000 WindowSize to calculate
+    -s STEPSIZE, --step=STEPSIZE
+        default:1000 StepSize for slide widows