Items are not recached until GAL is changed (earlier it was done on every rendering backend switch).

* Create separate NETLIST object to hold contents of netlist files.
* Read entire netlist and footprint link files before making applying
  changes to board.
* Add BOARD::ReplaceNetlist() function to eliminate the calls between the
  NETLIST_READER, PCB_EDIT_FRAME, and BOARD objects.
* Change placement of new components below the center of the current board
  or in the center of the page if the BOARD is empty.
* Add dry run option to netlist dialog to print changes to message control
  without making changes.
* Add button to netlist dialog to allow saving contents of message control
  to a file.
* Eliminate the need to compile netlist_reader_*.cpp in both CvPcb and Pcbnew.
* Add netlist_reader_*.cpp to the pcbcommon library.
* Remove redundant load component link file code from CvPcb.
* Modify CvPcb new to work with the new NETLIST_READER object.
* Add compare() function and < and == operators to FPID object.
* Add REPORTER class to hide an underlying string writing implementation for
  use in low level objects.  Thank you Dick for the idea.
* Lots of minor coding policy, Doxygen comment, and missing license fixes.

pcb_parser failed on (fill yes (arc_segments 16) (thermal_gap 1.99898) (thermal_bridge_width 1.99898))
See http://tech.groups.yahoo.com/group/kicad-users/message/15105

Removed BeginLayer and EndLayer functions. Resolved Cairo layers drawing problem in a different way.

Pcbnew: fix bug in pcb_parser: incorrect pad local solder paste margin ratio value read when not 0. ( This also fixes bug 1170535 )

Tidied up event handlers.