deep getter does not handle 'null/undefined' properties

[lewisparma]

I'm submitting a ... (check one with "x")

[x] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request => Please do not submit support request here

Current behavior
I have a dynamic set of objects as data source for the table. Some have a property called 'system' and others don't. If I bind a column to 'system.name' the deepValueGetter method will crash.

Expected behavior
deepValueGetter should expect that some properties in the middle of the path can be null/undefined..

Reproduction of the problem

a simple check if the property is null/undefined in deepValueGetter should fix the issue.

current = current[split[i]];
if (!current) {
return '';
}

What is the motivation / use case for changing the behavior?
Support a data source of objects that have a dynamic set of properties.

Please tell us about your environment:

• Table version: 0.7.x
  0.11.2
• Angular version: 2.0.x
  2.1.1
• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]
  Chrome
• Language: [all | TypeScript X.X | ES6/7 | ES5]
  Typescript

[amcdnl]

Fixed!

[lewisparma]

Thnks