Ability to have reusable variables across layers

[dbrody]

Current Limitation

Currently, content keys can only be complete values. A given item in the spreadsheet must be completely used within a text layer. It would be great to allow for partial values to be reused throughout a design.

Proposed Solution

Allowing variable names within content would help make content more easily dynamic. A example would be:

Key	Value
Name	ContentSync
Welcome	Welcome to {Name}

Using { ... } would allow for replacing the value of another key into the content of a key.

In this example, the value for key Welcome would be 'Welcome to ContentSync'.