fs: uids and gids must be unsigned ints

Before this commit, fs.chown() and fs.fchown() coerced the uid and gid
arguments to signed integers which is wrong because uid_t and gid_t are
unsigned on most all platforms and IDs that don't fit in a signed
integer do exist.

This commit changes the aforementioned functions to take unsigned ints
instead.  No test because we can't assume the system has [GU]IDs that
large.

This change depends on joyent/libuv@d779eb5.

Fixes #5890.
src: os: use Number::New() for CPU info

The return values from uv_cpu_info() don't necessarily fit in a 32 bits
signed integer.

Fixes #5732.
npm: Upgrade to v1.3.5
doc: explicitly set industry logo height
uv: Upgrade to v0.10.13
2013.07.25, Version 0.10.14 (Stable)

* uv: Upgrade to v0.10.13

* npm: Upgrade to v1.3.5

* os: Don't report negative times in cpu info (Ben Noordhuis)

* fs: Handle large UID and GID (Ben Noordhuis)

* url: Fix edge-case when protocol is non-lowercase (Shuan Wang)

* doc: Streams API Doc Rewrite (isaacs)

* node: call MakeDomainCallback in all domain cases (Trevor Norris)

* crypto: fix memory leak in LoadPKCS12 (Fedor Indutny)
Merge branch 'v0.10.14-release' into v0.10
Now working on 0.10.15
blog: Post for v0.10.14
doc: document tls.Server 'secureProtocol' option
src: fix process.getuid() return value

And process.getgid() too.

Commit ed80638 changed fs.chown() and fs.fchown() to only accept
unsigned integers. Make process.getuid() and process.getgid() follow
suit.

This commit should unbreak npm on OS X - it's hitting the new 'uid must
be an unsigned int' check when installing as e.g. user 'nobody' (which
has an UID of -2 in /etc/passwd or 4294967294 when cast to an uid_t.)

Fixes #5904.
2013.07.25, Version 0.10.15 (Stable)

* src: fix process.getuid() return value (Ben Noordhuis)
Merge branch 'v0.10.15-release' into v0.10
Now working on 0.10.16
blog: Post for v0.10.15
test: fix simple/test-setproctitle

The title shouldn't be too long; libuv's uv_set_process_title() out of
security considerations no longer overwrites envp, only argv, so the
maximum title length is possibly quite short.

Fixes #5908.
doc: add nodejs.org.au to community listing
doc: add nodejs.geek.nz to the community page
doc: clarify fs.read() offset argument
v8: upgrade to v8 3.20.9