Markings visibility and preferences consolidation

Exclude preferences are now an array. You can clean old thevirtualeuoccur.preferences.exclude_* from your brackers.json
Background color setting can contain CSS styles
Initial background setting is: background-color: #555; opacity: 0.7; border-radius: 6px;

Brackets Occurrences Marker

Allow time interval to be set from 0sec to 10sec.
0sec interval wil cause instant marking.
Default value is set to 0.2sec.

Brackets Occurrences Marker

Added configurable time interval.
Fixed unmarking.

Occurrences Marker Initial

Initial release