Remove extra spaces and tabs from README

README.md

@@ -54,19 +54,19 @@ The latest release of SourceSpec is available on the
 You can install it easily through `pip`:
 
     pip install sourcespec
-    
+
 ### From SourceSpec GitHub releases
 
 Download the latest release from the
 [releases page](https://github.com/SeismicSource/sourcespec/releases),
 in `zip` or `tar.gz` format, then:
 
-	pip install sourcespec-X.Y.zip
+    pip install sourcespec-X.Y.zip
 
 or
 
-	pip install sourcespec-X.Y.tar.gz
-	
+    pip install sourcespec-X.Y.tar.gz
+
 Where, `X.Y` is the version number (e.g., `1.2`).
 You don't need to uncompress the release files yourself.
 
@@ -78,7 +78,7 @@ code from the SourceSpec GitHub repository.
 
 For that, clone the project:
 
-	git clone https://github.com/SeismicSource/sourcespec.git
+    git clone https://github.com/SeismicSource/sourcespec.git
 
 (avoid using the "Download ZIP" option from the green "Code" button, since
 version number is lost), then install the code from within the `sourcespec`