use relative paths in simple.html example
extract subnet when parsing IPv4 addresses too
this.v4 = true in v4 constructor
added global function zeroPad(s, n);
v4 behaves like v4 now, with .bigInteger, .startAddress, .endAddress

Also added v4.Address.parse_u32(int_ip) as I often need this when
jamming with IPv4!
replaced v6.Address.zeroPad with global function.
Merge pull request #8 from dcolebatch/ipv4_fixes

IPv4 fixes from @dcolebatch
Add node 0.8
Add chai
Lint and clean

- Breaking change: v4.Address.parse_u32 to v4.Address.fromInteger
- Also just call fromHex under the hood since that's already written and integer
	to hex is easy!
Lint/fix tests, use chai's should
Remove extra space
Add tests for IPv4
Rename tests
Fix a bug found by @endor; add tests to verify

Plus some additional tests for related concerns and some IPv4-specific tests.
Fixes for v4/v6 subnets

And also be opinionated about correctness of subnets with leading zeroes.