Add "preexec" from "https://github.com/rcaloras/bash-preexec@0.4.1"

git-vendor-name: preexec
git-vendor-dir: vendor/github.com/rcaloras/bash-preexec
git-vendor-repository: https://github.com/rcaloras/bash-preexec
git-vendor-ref: 0.4.1

vendor/github.com/rcaloras/bash-preexec/.travis.yml

@@ -0,0 +1,20 @@
+language: bash
+
+before_install:
+  # To install bats and test our shell/bash functions
+  - git clone -b "v1.1.0" "https://github.com/bats-core/bats-core.git"
+  - sudo ./bats-core/install.sh /usr/local
+  - rm -rf ./bats-core
+  - sudo apt-get install -qq zsh
+
+# For bats functional tests
+env:
+  - functional_test="true"
+
+# command to run tests
+script:
+  - /usr/local/bin/bats test
+
+notifications:
+  email:
+    on_success: never