Empty tags during generation create an empty space on the final document

[leomrocha]

This is a topic that might cause usage problems, I suggest the following approaches:

1. If there are empty tags do not let generate the document, they need to input something (at least a space) or in that field select to leave it empty (maybe a checkbox or something)
2. Empty tags generate the template, but let there the template tags intact for that field i.e. {%%}
3. When there are empty tags warn the user and prompts to select which option to use from the options (1.) or (2.)

For usability I would add:

• A color code for empty or invalid fields as red (or yellow) and a mark that shows the user that needs to be filled (a warning sign next to the field for example )
• A color code as green when a field is filled correctly

In the future the idea is to add support for field type (being able to select if is numeric, text, date, currency ... )