Added ap-pipe and ap-compose macros
Added ap-pipe and ap-compose macros

`ap-pipe` is an anaphoric version of `->` and `->>`. It is useful for
specifying where the argument should go in each expression.

`ap-compose` returns a function which is the composition of several
anaphoric forms.

mtmiller/hy,gilch/hy,tuturto/hy,freezas/hy,ALSchwalm/hy,zackmdavis/hy,algernon/hy,Tritlo/hy,michel-slm/hy,paultag/hy,adamfeuer/hy,jakirkham/hy,timmartin/hy,kartikm/hy