title: countifs function with multiple conditions in excel file causes phpExcel to crash
body: <p>I'm using phpExcel class in a project.</p>
  
  <p>I created a model file with some formulas in its 2nd sheet which takes the data from 1st sheet. I'm writing all the data in the first sheet with phpExcel. Most of the formulas are working very well but there is one formula that causes a problem which is </p>
  
  <pre><code>=COUNTIFS(data!$R$2:$R$2000;"&lt;&gt;0";data!$R$2:$R$2000;"&lt;=90")
  </code></pre>
  
  <p>for the Excel 2007, the syntax differs in newer verison of Excel like</p>
  
  <pre><code>=COUNTIFS(data!$R$2:$R$2000,"&lt;&gt;0",data!$R$2:$R$2000,"&lt;=90")
  </code></pre>
  
  <p>I tried to write both formula to the cell with phpExcel also but it didn't work either. When I use this formula , I get no error or feedback , the script just stops working.</p>
  
  <p>I would be glad if you could show me a way to solve this issue.</p>
  
  <p>Regards</p>