code: public void setVariableEsc(String variableName, String variableValue, boolean isOptional)
              throws VariableNotDefinedException {
          setVariable(variableName, escapeHtml(variableValue), isOptional);
      }
docs: Sets a template variable to an escaped value.
  <p>
  Convenience method for:
  <code>setVariable (variableName, MiniTemplator.escapeHtml(variableValue), isOptional)</code>
  
  @param variableName the name of the variable to be set.
  @param variableValue the new value of the variable. May be <code>null</code>. Special HTML/XML characters are
  escaped.
  @param isOptional specifies whether an exception should be thrown when the variable does not exist in the
  template. If <code>isOptional</code> is <code>false</code> and the variable does not exist, an
  exception is thrown.
  @throws VariableNotDefinedException when no variable with the specified name exists in the template and
  <code>isOptional</code> is <code>false</code>.
  @see #setVariable(String, String, boolean)
  @see #escapeHtml(String)