Release 1.6

This release contains the following changes:

• [Feature] --start-hidden to hide the cursor initially when unclutter-xfixes starts.
• [Feature] --ignore-buttons to specify one or more buttons which do not unhide the cursor.
• [Feature] --hide-on-touch to hide the cursor on touch input.
• [Fix] --timeout now supports non-integer values.
• Various improvements to the man page.