now using bash for everything

ts/npmci.install.ts

@@ -1,5 +1,7 @@
 import "typings-global";
 import * as plugins from "./npmci.plugins";
+import {bash} from "./npmci.bash";
+
 export let install = (versionArg) => {
     let done = plugins.q.defer();
     let version:string;
@@ -9,12 +11,9 @@ export let install = (versionArg) => {
         version = versionArg;
     };
     plugins.beautylog.log("now installing " + "node ".green + ("version " + version).yellow);
-    plugins.shelljs.exec(
-        "bash -c \"source /usr/local/nvm/nvm.sh && nvm install "+
-        version +
-        " nvm alias default " +
-        version +
-        "\""
+    bash(
+        "nvm install " + version +
+        " nvm alias default " + version
     );
     plugins.beautylog.success("Node version " + version + " successfully installed!");
     plugins.shelljs.exec("node -v");