Merge tag 'v0.2.1'

v0.2.1
Add v0.11+ requirement note to README
Update contribution guidelines

Replace commit signing process with https://cla.strongloop.com/
debug server: unref only the server handle, not the stream
Zone: improve error message on assertion failure
test: add test for write callbacks
Make jshint happy
stream-wrap: re-implement with correct refcounting semantics
Make the test runner work on windows and linux

For windows users to be able to run tests, they have to install
either MSys, or Cygwin, or Git for Windows, and have it available
on their path.
test: rename test to be non-case-sensitive FS compatible
coverage: Add test coverage
lint: Fix lint errors
src: Rename more to be non-case-sensitive compat.
Revert "coverage: Add test coverage"

This commit breaks the test runner on windows again.
This reverts commit bd0e1281c4f5551f18dc2d3613177a5f0e0cf67b.
Don't unregister ProcessWrap from zone when signaled

Just try to kill it instead. If the process exits, it'll unregister
itself.
stream-wrap: add node 0.10 support
Make NativeModule work with node v0.10
Fix long stack formatting for node v0.10
Add node v0.10 detection helper
require: split up v0.10 and v0.12 require() hooks