Add a task that will remove github labels from an issue.

Refs #7.

gruel/src/main/groovy/com/glasstowerstudios/gruel/tasks/github/ListGithubIssuesTask.groovy

@@ -0,0 +1,18 @@
+package com.glasstowerstudios.gruel.tasks.github
+
+import com.glasstowerstudios.gruel.tasks.github.GithubTask
+import org.gradle.api.tasks.TaskAction
+import org.kohsuke.github.GitHub
+import org.kohsuke.github.GHRepository
+import org.kohsuke.github.GHIssueState
+
+class ListGithubIssuesTask extends GithubTask {
+  @TaskAction
+  def doTask() {
+    def repo = getRepository()
+    def issues = repo.getIssues(GHIssueState.ALL);
+    for (def nextIssue : issues) {
+      println "Issue #" + nextIssue.number + ": " + nextIssue.title
+    }
+  }
+}

gruel/src/main/groovy/com/glasstowerstudios/gruel/tasks/github/RemoveLabelsFromGithubIssueTask.groovy

@@ -0,0 +1,46 @@
+package com.glasstowerstudios.gruel.tasks.github
+
+import com.glasstowerstudios.gruel.tasks.github.GithubTask
+import org.gradle.api.tasks.TaskAction
+
+/**
+ * A type of {@link GithubTask} that will remove a set of labels from the github
+ * issue having a specified issue number.
+ */
+class RemoveLabelsFromGithubIssueTask extends GithubTask {
+  public static final String ALL = "all"
+
+  private int issueNumber;
+  private List<String> labels;
+
+  void setIssueNumber(int issueNumber) {
+    this.issueNumber = issueNumber;
+  }
+
+  void setLabels(List<String> labels) {
+    this.labels = labels;
+  }
+
+  List<String> getLabels() {
+    return this.labels;
+  }
+
+  int getIssueNumber() {
+    return this.issueNumber;
+  }
+
+  @TaskAction
+  def doTask() {
+    def repo = project.github.connectToRepository()
+    def issue = repo.getIssue(this.issueNumber)
+    def issueLabels = issue.getLabels()
+    def labelsToKeep = []
+    for (def nextLabel : issueLabels) {
+      if (!this.labels.contains(nextLabel.getName())) {
+        labelsToKeep << nextLabel.getName()
+      }
+    }
+
+    issue.setLabels(labelsToKeep as String[])
+  }
+}