Update DPF, some misc fixes

This updates to the latest DPF code (which includes your ImageKnob changes now)
UI widgets now use ScopedPointer, so there's no more mem leaks there.
I fixed some other minor things as well.

the makefiles are updated too, use "make NOOPT=true" to skip optimizations (useful in debian packages).

hope to see you online soon, I have questions about some code