Files with upper case endings are not detected as valid images #247
Description
Latest develop 9795c55: If a file has an upper case file ending of a normally detected valid image format, it won't be accepted by rascsi unless you specify the device type.
pi@rpi3b:~/RASCSI/src/web $ rasctl -i 0 -c attach -f ~/images/zxcv.HDS
Error: No device type provided for unknown file extension 'HDS'