Add lcomposition fixity to support (>>) in the stdlib

[paulcadman]

The stdlib composition function ∘ has fixity composition which means it is right associative.

We will rename ∘ to << in the stdlib and add a new function:

>> {a b c} : (a -> b) -> (b -> c) -> a -> c

for consistency with << this should be left associative.

This is not a breaking change to package-base so we don't need to increment the version number.