package: add test.js as npm test script

Also, make it print something on success, its comforting.
Remove unused function export from binding

Removing it allows the Persistent<> to be removed, and the APIs around
persistents are more complex in v0.11. Also, removed unnecessary
`function(){...}();` wrapper around module (node does that itself).
Removed unused ObjectWrapper base from Syslog
Remove unused persistent callback to log()

log() allowed a callback to be passed as arg[3], but arg[2] was unused,
and the callback was never called (and not documented).
Support v0.10 through v0.11.13

The compatibility library is borrowed under ISC license from
bnoordhuis/node-heapdump.
fixup! add and use Return() overload for int
Merge pull request #33 from sam-github/feature/v0.11-support

Feature/v0.11 support
Build an empty addon on win32

Npm does not support platform sensitive dependencies, and will always
attempt to build syslog even if its not going to be used. The error
messages are disturbing to naive users. Instead, compile syslog into a
an empty addon, so that it builds sucessfully, but won't have an .init()
method. This supports run-time detection of syslog capability, rather
than npm install time build failures.