ENYO-1420: faster timeout when phonegap is not reachable.

- add configurable timeout when calling build.phonegap.com (default: 7s)
- report actual service error string when checking account

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
ENYO-1420: use constant for timeout rather than numeric value.
Merge pull request #336 from enyojs/ENYO-1420

ENYO-1420: faster timeout when phonegap is not reachable.