Add default implementation on POSIX.
Link with gnome-keyring.
Implement with gnome-keyring on Linux.
Suppress compiler warning.
findPassword doesn't guarentee to return first password.
:memo: Update docs for Linux.
Add travis CI.
Install dependency in cibuild.
Print error message.
Start gnome-keyring-daemon.
Install gnome-keyring.
Export environments of gnome-keyring-daemon.
Start xvfb as virtual display.
Tweak with gnome-keyring-daemon parameters.
Do not run specs.

We always get "Error communicating with gnome-keyring-daemon" error,
could not find out why.
:lipstick: Fix English grammer error.
Merge pull request #5 from atom/linux

Implement with gnome-keyring on Linux