boot2docker 0.8.1

bump version 0.8.1 + sha1 checksum

Closes #29064.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Fixed shared documents (Documentation, Examples, etc.) not being linked into the "share" folder
Fixed executables being moved to wrong direcory "share" introduced with previous commit.
pebble-sdk: update 2.1 bottle.