Always set FG color when bg image is set

Push hotfix

Try to better handle background images on elements

Disable mutation observer when restoring our data attributes to prevent

infinite loop (should address GH-49)

Formatting fixes

Rebuild to remove console logging code.

Last version must have not been rebuilt one last time, so the xpi file had
some leftover console.log statements. This version removes them.

Make sure probe frame does not use display=none, otherwise colors don…

…'t seem to read correctly.

Use parent-following contrast checker when only handling inputs too (…

…should fix #48).

Bump version for bugfix release

Re-organize css handling in makefile to fix missing css file