title: Trying to implement FPDF with all forms of instantiation but only one form works. Others give Error
body: <p>Installed crabbley/fpdf-laravel as per instructions. Tried some sample code as follows:</p>
  
  <pre><code>$pdf= app('FPDF');
  $pdf-&gt;AddPage();
  $pdf-&gt;SetFont('Arial','B',16);
  $pdf-&gt;Cell(40,10,'Swordsmen Class Times');
  $pdf-&gt;Output();
  </code></pre>
  
  <p>While the instantiation of fpdf is different from the samples in the tutorials, all works as expected and the pdf is displayed in the browser. I got this working sample from the crabbley packagist.org/packages/crabbly/fpdf-laravel readme under 'usage'. The 'usage' instructions also provide an alternative instantiation viz: <code>$pdf = new Crabbly\FPDF\FPDF;</code>
  The tutorial samples use something slightly different again, ie</p>
  
  <pre><code>require('fpdf.php');
  x=new FPDF();
  </code></pre>
  
  <p>and thus are a little different. When I changed it to be the same as the tutorial, all I changed was the instantiation line from </p>
  
  <pre><code>$pdf= app('FPDF');
  </code></pre>
  
  <p>to </p>
  
  <pre><code>$pdf = new FPDF('L', 'mm','A4');
  </code></pre>
  
  <p>and I get the error 'Class 'App\Http\Controllers\FPDF' not found'. I do not understand the difference between the different forms of instantiation and not sure what is going on but I need the latter format so I can set page orientation etc. I also tried the usage format as described above with the same sort of error, ie new Crabbly\FPDF\FPDF not found.
  I have tried the require statement but FPDF is not found and I am unsure where to point 'require' to.</p>
  
  <p>Installation consisted of:
  composer require crabbly/fpdf-laravel
  add Crabbly\FPDF\FpdfServiceProvider::class to config/app.php in the providers section</p>
  
  <p>Any suggestions will be appreciated.</p>