[Bug 870178] fetch_appcache and related resource into cache/
support fetch offline path
make exception more specific
Merge pull request #19 from gasolin/fetch_appcache

[Bug 870178] fetch_appcache and related resource into cache/ r=yurenju
Merge pull request #20 from gasolin/test_fix

fix unittest r=yurenju fixed #16
added travis support
Merge pull request #21 from yurenju/travis

fixed #17: added travis support