Merge pull request #1921 from libm/nw0.8

Move aws key id settings into boto config file.
Backport build-in menu to nw0.8
Merge pull request #1936 from gitchs/backporting

Backport build-in menu to nw0.8
Solve Windows&Linux build error
Merge pull request #1941 from gitchs/backporting

Solve Windows&Linux build error
bump version to 0.8.7-rc2
Support for 'single-instance' when app is started in folder

Fix #515
bump version to 0.8.7-rc3
Flush stdout to inform buildbot that it is not hang.

Added retry and let 'node-webkit-' bundle to be uploaded first.