Tests, documentation update

Author: gdy

README.md

@@ -35,9 +35,11 @@ Features:
 	}
 
 	dependencies {
+	 	// versioning: master-SNAPSHOT (lastest build, unstable), + (lastest release, stable) or certain version (e.g. 1.0)
 		compile 'com.github.ProjectKaiser:pk-vcs-git:master-SNAPSHOT'
 	}
 	```
+	Or download release jars from https://github.com/ProjectKaiser/pk-vcs-api/releases  
 - Create Workspace Home instance providing path to any folder as Workspace Home folder path. This folder will contain repositories folders (if different vcs or repositories are used)
 ```java
 	public static final String WORKSPACE_DIR = System.getProperty("java.io.tmpdir") + "git-workspaces";

src/test/java/com/projectkaiser/scm/vcs/GitVCSTest.java

@@ -83,10 +83,12 @@ public void setUp() throws Exception {
 
 	@After
 	public void tearDown() {
-		try {
-			gitHubRepo.delete();
-		} catch (IOException e) {
-			// do not affect the test
+		if (gitHubRepo != null) {
+			try {
+				gitHubRepo.delete();
+			} catch (IOException e) {
+				// do not affect the test
+			}
 		}
 	}