Implement fail-fast in runner

Report tracks number of omitted tests due to abort.

spec/report_spec.cr

@@ -71,6 +71,15 @@ describe Spectator::Report do
     end
   end
 
+  describe "#remaining_count" do
+    it "is the expected value" do
+      results = [] of Spectator::Result
+      remaining = 5
+      report = Spectator::Report.new(results, Time::Span.zero, remaining)
+      report.remaining_count.should eq(remaining)
+    end
+  end
+
   describe "#failed?" do
     context "with a failed test suite" do
       it "is true" do
@@ -87,6 +96,24 @@ describe Spectator::Report do
     end
   end
 
+  describe "#remaining?" do
+    context "with remaining tests" do
+      it "is true" do
+        results = [] of Spectator::Result
+        report = Spectator::Report.new(results, Time::Span.zero, 5)
+        report.remaining?.should be_true
+      end
+    end
+
+    context "without remaining tests" do
+      it "is false" do
+        results = [] of Spectator::Result
+        report = Spectator::Report.new(results, Time::Span.zero, 0)
+        report.remaining?.should be_false
+      end
+    end
+  end
+
   describe "#failures" do
     it "returns the expected results" do
       results = Array.new(5) { new_failure_result.as(Spectator::Result) }