Add new <> name and new syntax to let macros
(by ...) form properly threads the topic through the updater
Add <> symbol to nearly all synthread macros

The diamond (<>) symbol is now bound and rebound to the current topic as it is
threaded through the forms. This behavior is consistent across all macros
except in the as and aside macros.

Actually those two macros may no longer be needed and so deprecated.
;; equivalent
(->/as foo ...)
(->/let [foo <>] ...)

;; equivalent
(->/aside foo ...)
(->/let [foo <>] (doto (do ...)))
Add ->/side macro, add <> symbol to ->/as macro

The <> symbol is now bound to the current topic inside the ->/as body as well.
A new ->/side macro now support a non-threaded body but also has a <> bound to
the topic. The new macro doesn't need to explicitly bind the topic thanks to
the automatic binding.
bump to 1.1.0-SNAPSHOT