Customfields

Might be worth considering using a different methodology to remove the `custom.` prefix.  The logic you're using here could run into trouble if the string "custom." appears more than once in the key. A small change would make this less prone to error during exceptional circumstances. 

Some options:

```coffeescript
for key, value of flatten(vars.velocify)
  # make sure the "custom." appears at the front of the key
  if key.indexOf('custom.') == 0
    # remove only the "custom." prefix
    key = key.replace(/^custom\./, '')
    content[key] = value?.toString()
```

Or

```coffeescript
for key, value of flatten(vars.velocify)
  # use a regex to test for the "custom." prefix and a match group to 
  # extract the remainder of the key
  if match = "custom.foo.bar".match(/^custom\.(.*)/)
    content[match[1]] = value?.toString()
```