Previously a TemplatedSnippet could only write snippets with the
same name as its template. This meant that the same template could
not be used to produce multiple snippets with different names.
This commit separates the snippet name from the template name, thereby
allowing the snippet name to vary while the template name remains the
same. For backwards compatibility, the default behaviour is for the
template name and snippet name to remain the same. The new overloaded
constructor can be used when the names need to differ.
Closes gh-320
4f19294220