Failure to create new element

[bdeanindy]

While trying to add a new element, I received a few different errors (and in some cases, did not receive errors when I probably should)...

Should we:

1. Be able to use hyphens, underscores or other characters in app, element, and element setting names/labels?
2. Perform some type of verification on the element setting type radio items?
3. Support an interactive prompt for the element's icon to permit tab-completion of paths?
4. Do we rename whatever icon is provided to the expected icon.svg (or can we change that filename in our app)?
5. We should probably permit hyphens and underscores in element and element settings' names used in code
6. We should probably include some interactive confirmations on what we're creating for element settings.

[bdeanindy]

Resolved 1 and 5 above in Issue #11