Add basic sqlite error handling to the new sqlite handlers...

app/sql/statement.h

Index: app/sql/statement.h
===================================================================
--- app/sql/statement.h	(revision 27122)
+++ app/sql/statement.h	(working copy)
@@ -22,6 +22,10 @@
 //   s.BindInt(0, a);
 //   if (s.Step())
 //     return s.ColumnString(0);
+//
+// Step() and Run() just return true to signal success. If you want to handle
+// specific errors such as database corruption, install an error handler in
+// in the connection object using set_error_delegate().
 class Statement {
  public:
   // Creates an uninitialized statement. The statement will be invalid until
@@ -110,6 +114,11 @@
   void ColumnBlobAsVector(int col, std::vector<char>* val) const;
   void ColumnBlobAsVector(int col, std::vector<unsigned char>* val) const;
 
+  // Diagnostics --------------------------------------------------------------
+
+  // Returns the original text of sql statement. Do not keep a pointer to it.
+  const char* GetSQLStatement();
+
  private:
   // This is intended to check for serious errors and report them to the
   // connection object. It takes a sqlite error code, and returns the same