Support NFS back

https://github.com/boot2docker/boot2docker/pull/337
Do not delete sunrpc
Add CONFIG_NFS_V4_1 and CONFIG_NFSD_TCP
Change m to y for CONFIG_NFSD
prepare for next release
it seems that 3 seconds is not enough time for Hyper-V to have the disk ready (Closes #406) - trying 10 for now
Merge pull request #416 from SvenDowideit/pr_out_it_seems_that_3_seconds_is_not_enough_time_for_hyper_v_to_have_the_disk_ready_closes_406_trying_10_for_now

it seems that 3 seconds is not enough time for Hyper-V to have the disk ready (Closes #406) - trying 10 for now
Merge pull request #349 from YungSang/nfs

Support NFS back
Merge pull request #415 from SvenDowideit/pr_out_prepare_for_next_release

prepare for next release
update to 3.15.3 Linux kernel
add retry to kernel curl, my net was up and down like mad
change the build instructions to be more like what I actually do
the 3.15.3 .config we built with
Merge pull request #419 from SvenDowideit/update-to-3.15.3-linux-kernel

Update to 3.15.3 linux kernel