Trying to enable maven cache in travis. Add travis badge. Fix bug in

source file copier

.travis.yml

@@ -1,3 +1,8 @@
 language: java
 jdk:
   - oraclejdk8
+cache:
+  directories:
+  - $HOME/.m2
+after_script:
+  - rm -rf $HOME/.m2/repository/org/teavm

README.md

@@ -1,6 +1,8 @@
 TeaVM
 =====
 
+[![Build Status](https://travis-ci.org/konsoletyper/teavm.svg?branch=selenium)](https://travis-ci.org/konsoletyper/teavm)
+
 What is TeaVM?
 --------------
 

tools/maven/plugin/src/main/java/org/teavm/maven/MavenSourceFileProviderLookup.java

@@ -85,7 +85,12 @@ public class MavenSourceFileProviderLookup {
             ArtifactResolutionResult result = repositorySystem.resolve(request);
             for (Artifact resolvedArtifact : result.getArtifacts()) {
                 if (resolvedArtifact.getFile() != null) {
-                    providers.add(new JarSourceFileProvider(resolvedArtifact.getFile()));
+                    File file = resolvedArtifact.getFile();
+                    if (!file.isDirectory()) {
+                        providers.add(new JarSourceFileProvider(file));
+                    } else {
+                        providers.add(new DirectorySourceFileProvider(file));
+                    }
                 }
             }
         }