add method-style call syntax

[mccanne]

This commit adds a new calling syntax where a.foo(b,...) is equivalent foo(a,b,...). Docs will be updated in a future PR.

[nwt]

Nits: This is something we can debate later, but I think this operator should be |> or -> instead of . for a few reasons:

1. To clarify to the reader that they're looking at a function application rather than a field reference (even more than the parentheses do)
2. In a similar vein, to avoid the implication that the function is in some way a method bound to the operator's LHS rather than a plain old function
3. To make room for |>> or ->> as a forward-last/thread-last/pipe-last operator where a |>> f(b) is equivalent to f(b, a)