ENYO-3765: add back "3.0.0" as a supported Phonegap version

ENYO-3765: add back support for PhoneGap version 3.0.0

As per JIRA https://enyojs.atlassian.net/browse/ENYO-3765
See discussion on PGB support site here: http://community.phonegap.com/nitobi/topics/is_phonegap_3_0_0_still_supported 

Enyo-DCO-1.1-Signed-off-by: Francois Connetable <francois.connetable@hp.com>