Install vundle only on the linux branch
Better bootstrap script

- Ask user confirmation before running.
Revert "Better bootstrap script"

This reverts commit 290696eb29cd2143e69f26109ee6d131fa0dd8ac.
Revert "Revert "Better bootstrap script""

This reverts commit 02bab906a144b66794b969fe7e062148b0ffcd6a.
Revert "Install vundle only on the linux branch"

This reverts commit 83103bf1670aff9548b051034ae971370c3df82a.