Possibility to leave a field empty

[sandersantema]

Currently adding a note like the following wouldn't be possible:

Template:

# {Front}
# {Back}
# {Hint}

Note:

# Front Example
# Back Example

This would be good to have since you might for instance not want to add a hint to every note but use the same template non the less.

This would hopefully also allow for the following:

Template:

# Front
{Front}
# Back
{Back}
# Hint
{Hint}
# Source
{Source}

Note:

# Front
Front Example
# Back
Back Example
# Hint

# Source
Example Source