Use opencpn.spec.in specfile to build rpm

As of rpm 4.10 (Fedora 18), cmake built rpm cannot be installed
 file /usr from install of opencpn-xxx conflicts with file from package filesystem-yyy
 ...
See http://public.kitware.com/Bug/view.php?id=12864 for reference.
cmake/cpack RPM: we don't own %{_datadir}/doc
In DashboardInstrument_Dial::Draw DrawData(ExtraValue) should be done after DrawBackground for proper visibility
Correct Track start Timestamp calculations
Implement multi-selection capability for RouteManagerDialog lists
Improve Context menu "Send to GPS" port selection logic
Increase selection "hot spot" radius for Tide icon.
Remove "Export All" button from RouteManagerDialog
Improve Dashboard text rendering for small text size.
Prevent deletion of Dashboard window as parent of Preferences dialog
Increase Dashboard watchdog timeout value to 10 sec.
Improve linux/Mac Serial device detection
Correct initial Dashboard visibility logic
Revert linux libtinyxml dependency to 2.6.2
Correct Mark Info links with embedded spaces on linux
Correct partial hang on Windows when no network interface is available.
Improve Datastream serial port thread isolation.
Add full help manual to Mac DMG installer.
Improve linux serial port detect logic
Documentation update