Initial attempt at travis-ci integration

This is the initial attempt to integrate the easyrsa project with
travis-ci by merging szepeviktor-master.  Additional work is necessary,
but this gets us going in the right direction.  Closes #165.

Signed-off-by: Eric F Crist <ecrist@secure-computing.net>

.travis.yml

@@ -0,0 +1,13 @@
+language: bash
+
+sudo: false
+
+addons:
+  apt:
+    sources:
+    - debian-sid
+    packages:
+    - shellcheck
+
+script:
+ - bash -c 'shopt -s globstar; shellcheck **/*.sh easyrsa3/easyrsa'