remix of BV3D solidoodle carriage added bearings and stronger sides

i like BV3D's design for the carriage ends as it added extra print space, but after almost a year of printing i just noticed (i think i broke a few months back and i thought my bed was out of alignment) that the motor end of the carriage has rather large cracks through the thin sides...

i added much larger radius fillets though out to make the sides stronger and i think it looks nicer. and i also added holes for 8*5*2.5mm flange bearings for the idle end of the carriage..

thanks for th