more docs

lots more. it feels as if it makes loading slower, though.
fix typo
uncomment disj! for now, as -disj! doesn't exist yet
add repeat
support printing the docs of all symbols in a namespace
print name and signatures of the value in question
fix typo
add doseq
move inline examples into a ^:examples metadata key

they're vectors of strings (one per example) currently, and evaluated
when being displayed. not sure about that, but at least it ensures
they are correct.
represent ^:examples as a vector of vectors

an example is a vector of [expr output val], where expr is a string
containing a read-string'able expression, output is a string containing
the output that is printed when evaluating the expr and val is the value
returned.

this allows checking the examples automatically, prettier doc output and
potential use of this metadata.
test doc examples as part of the test suite
extract signatures from defn if not explicitely specified
fix update-in
print signatures even if no docstring is present
add signatures for map
move update-in closer to *-in and add tests
Merge pull request #95 from heyLu/docsdocsdocs

Docs, quite a few docs.