Some checks for Clearness index to keep ìt between 0 and 1

[raghu1121]

It seems in some scenarios i observed KT > 1 and ZeroDivisionError. So i made changes to my own code like this. This might be helpful for others.

    try:
        KT = (ghi_data / EXTR1)
        if KT > 1:
            KT = 1
    except ZeroDivisionError:
        return 0
    return KT 

[pingswept]

Fixed by commit 6185507. Thanks for the patch!

[pingswept]

Sorry, had to revert this, as it broke the build.

This broke the build with this error on Python 3.4:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

I suspect this could be fixed pretty easily if anyone has the inclination.