Maven repo url

See merge request !1044

url must be unique

See merge request !1043

Resolve "there is possibility to perform xss attack that inserts malicous javascript as plugin url"

See merge request !1042

Resolve "Add additional information in overlay dialog"

See merge request !1038

Resolve "Data overlay - colouring by column identifier_xxx does not work"

See merge request !1037

Resolve "this exception is not handled properly (on project remove)"

See merge request !1035

Resolve "if map has SHOW OVERVIEW, the legend/comment/clear are not displayed at all"

See merge request !1034

when there is no background don't check if overlay is nested

See merge request !1032