added documentation about supported stream APIs
added .isEnded()
better .isReadable(), .isWritable()
added .isCorked()
doc: added notes about the streams3 API

added notes about the streams3 API for readable._readableState
package.json: ask for node v0.11.5 or later

node v0.11.5 or later for "streams3"
Merge branch 'dev-test-methods' into dev
added documentation

added documentation for .isEnded(), .isCorked()
Merge branch 'doc' into dev
added test for .extend() / .isCorked()
added tests for .isEnded()
new version 0.2.0