Reads the common format self.data and writes out to a dataframe.

def to_dataframe(self):
        """
        Reads the common format self.data and writes out to a dataframe.
        """
        keys = self.data[0].keys()
        column_list =[]
        for k in keys:
            key_list = []
            for i in xrange(0,len(self.data)):
                key_list.append(self.data[i][k])
            column_list.append(key_list)
        df = DataFrame(np.asarray(column_list).transpose(), columns=keys)
        for i in xrange(0,df.shape[1]):
            if is_number(df.iloc[:,i]):
                df.iloc[:,i] = df.iloc[:,i].astype(float)
        return df