boost: bump version to 1.53.0

and re-enable boost context library since its compilation with
uClibc is fixed. Disable new atomic library because it can not
compile with uClibc (fixed in upstream version).

Signed-off-by: Victor Hiairrassary <victor.hiairrassary.ml@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>