Change ':' in cachefolders to '_' on windows

Fixes #24
Keep : out of cache paths
v0.2.26
graceful-fs@2.0.0
v0.2.27
bump deps: semver, request, couch-login
v0.2.28
semver@2.2
v0.2.29
Do not send auth unless necessary
v0.2.30
userobj should not overwrite data.roles for existing user
Allow localAddress for requests to be set via config using "local-address"
add support for client cert/key, needed by https/tls

Pass-through cert and key to couchLogin to support https/tls client
certificate features needed when npm connects to a registry that
requires client certificates.
Add a `.deprecate` method
Add `.bugs` method
v0.2.31
Atomic publish

instead of the problematic 3-stage PUT process, just do one PUT with the
tarball data inline.
v0.3.0
calculate hash of the tarball, not the base64 encoded tarball