#692 Marking of new entries and often read entries

[Anonymous]

This is a patch containing both a marker for unread entries and a bar visualizing how often an entry has been read.
It adds a new column to the main table showing a small star icon if the entry is unread or read only once.
The star will disappear when opening the entry for the second time. The cell will then display a bar representing the read frequency of an entry. The entry read most often will display a bar completely filling the cell. Other entries' read count bars are proportionally shorter according to their respective read counts.

Example:
Entry 1 has been read 10 times -> gets 100\% filled\\
Entry 2 has been read 3 times -> gets ~33\% filled\\
Entry 3 has been read 2 times -> gets 20\% filled\\
Entry 4 has been read 1 time -> still has the star for new entry

[Nobody/Anonymous]

patchfile, readme and icons. please refer to readme for installation advice

[Igor]

Fixed and merged. Pull request #28
https://github.com/JabRef/jabref/pull/28