Update boost required to 1.49 as 1.48 fusion has bugs on 64bit linux.
Update ParameterPacks to compile with pre gcc 4.6.

pre gcc 4.6 has some interesting bugs in parsing variadic code that
we need to work around.
Update code to compile with pre gcc 4.6.

pre gcc 4.6 has some interesting bugs in parsing variadic code that
we need to work around.