Clean the code according to review - reformat, change modifiers etc.

* Indentation - reformatted file with 4 spaces tab
* Initialization - initialized with a default initializer.
* Changed the field `commits` to private
* Added missing new line at the end of file.
* Made the new function public.

tcslackbuildnotifier-core/src/main/java/slacknotifications/teamcity/payload/content/PayloadContentCommits.java

@@ -11,13 +11,13 @@
 import java.util.List;
 
 public class PayloadContentCommits {
-    List<Commit> commits;
+    private List<Commit> commits;
 
     public PayloadContentCommits() {
         commits = new ArrayList<Commit>();
     }
 
-    void populateCommits(SRunningBuild sRunningBuild) {
+    public void populateCommits(SRunningBuild sRunningBuild) {
         List<SVcsModification> changes = sRunningBuild.getContainingChanges();
         if (changes == null) {
             return;
@@ -42,4 +42,4 @@ public List<Commit> getCommits() {
     public void setCommits(List<Commit> commits) {
         this.commits = commits;
     }
-}
+}