title: counting the amount of True/False values in a pandas row
body: <p>Is there a way in pandas to calculate how many True or False conditions are there in a column. </p>
  
  <p>eg: If a data frame has 5 columns and I want to select rows with at least three columns with values > 3, can this be done without the use of an iterator?
  So in the example below i will select rows b and c. </p>
  
  <pre><code>In [12]: df2
  Out[12]: 
         A   B  C   D   E
      a  1   2  2   8   6
      b  3   6  5   8   8
      c  6   2  5   5   2
  </code></pre>