BF+ENH/RF(TST): more of binding fixups, enhance testing setup

[yarikoptic]

grr, the 2nd run on travis errors in the first test on passing args to docker: https://travis-ci.org/github/ReproNim/containers/jobs/750269398#L1558

with "/usr/local/bin/docker: unhandled command line:"

```shell /usr/local/bin/docker: unhandled command line: $1 = $2 = <--privileged> $3 = <--rm> $4 = <-e> $5 = $6 = <-e> $7 = $8 = <-v> $9 = $10 = <-v> $11 = $12 = <-v> $13 = $14 = <-v> $15 = $16 = <-w> $17 = $18 = <-v> $19 = $20 = $21 = $22 = <-B> $23 = $24 = <-B> $25 = $26 = <-e> $27 = <-B> $28 = $29 = <-H> $30 = $31 = <--pwd> $32 = $33 = $34 = $35 = $36 = $37 = <45.5> $38 = $39 = $40 = $41 = <${foo}> FAIL: Arguments are not equal. #1=<<1>> #2=<<0>> not ok 1 verifying arguments passed to singularity_cmd Docker shim # (from function `myrun' in file scripts/tests/test_helpers.bash, line 28, # in test file scripts/tests/test_singularity_cmd.bats, line 30) # `myrun scripts/singularity_cmd \' failed # latest: Pulling from repronim/containers # Digest: sha256:e906fda34b081178b0fbf89818da3509f958fcb7e6d36bd69204665fb7675d5d # Status: Image is up to date for repronim/containers:latest # docker.io/repronim/containers:latest # > Running "scripts/singularity_cmd exec /Users/travis/build/ReproNim/containers/scripts/tests/arg-test.simg /singularity foo bar blah 45.5 /dir bar; foo& ${foo}" ```

which is "correct to fail" since we did add a new bind mount option to docker to bind mount /tmp itself. So I just wonder why it has not failed locally... will dig in again, uff

[yarikoptic]

ah, right -- that travis dummy one is one of ours! ;)

travis/install.sh:    sudo cp travis/dummy_docker /usr/local/bin/docker

fixed up, pushed

[yarikoptic]

out of patience -- what was failing now doesn't. linux run of travis is yet to happen, so will proceed and merge