Started converting the header check.

Oliver, this checkin is mainly to keep you informed what I am doing so
that we avoid duplicate work. Please email me once your ISP starts working
again (do you have an alternate email address or a webmail account?)

src/checkstyle/com/puppycrawl/tools/checkstyle/checks/HeaderCheck.java

@@ -0,0 +1,29 @@
+package com.puppycrawl.tools.checkstyle.checks;
+
+import com.puppycrawl.tools.checkstyle.api.Check;
+
+/**
+ * Checks that the header of the source file is correct.
+ *
+ * <p>
+ * Rationale: In most projects each file must have a fixed header,
+ * usually the header contains copyright information.
+ * </p>
+ *
+ * @author Lars Kühne
+ */
+public class HeaderCheck extends Check
+{
+    /** @see Check */
+    public int[] getDefaultTokens()
+    {
+        return new int[0];
+    }
+
+    /** @see Check */
+    public void beginTree()
+    {
+        String[] lines = getLines();
+        log(0,"file has " + lines.length + " lines");
+    }
+}