Example error resulting from attempting to put `nil` on a channel was
using integer 42

update API reference link

changes: CI integration section

changes: async testing section

changes: unit testing first steps section

changes: unit testing intro

Large number of changes. Added:

Section for namespaces and filenames
Example of a shape not in hierarchy
Calling functions like j...

clarify: transition from build scripts to Leiningen

formatting: remove space from ` export`

rephrase: first lein project intro

additions: first lein project building

changes: 'managing dependencies' section

typo: momenent -> moment

corrections: Google Closure Library section

corrections: nodejs repl section

grammar/phrasing: section on advanced compilation

grammar: 'levels of optimization'

typo: Then -> When.

clarify reason for applying aget/aset to objects

add `specify!` to Protocols section

add 'property access shorthand' to interop section

clarify reify

typo: snipped -> snippet

remove unsupported `:refer :all` directive

correct default namespace to be cljs.user

High-level core.async abstractions

Closes #63

replace PersistentQueue.EMPTY with #queue []

reword potentially confusing comparison of maps and vectors

fix statement about nil being seqable and sequence

typo: xpractical -> practical

typo: ouf -> out of

Proofread basics through line 1100.

Added a reference to macros in advanced section.

Var, not symbol, should be passed to defmulti as :hierarchy option.

managemen -> management

refs #50

Csp and core async