mpc: convert to new package format, move package

Signed-off-by: Stephan Raue <stephan@openelec.tv>
mpfr: convert to new package format, move package

Signed-off-by: Stephan Raue <stephan@openelec.tv>
ppl: move package, cleanup

Signed-off-by: Stephan Raue <stephan@openelec.tv>