Fixed bugs 2981754 and 2981759 (PCBnew crash when trying to add a new net name to a pad) Linux specific, and perhaps due to a bug in wxGTK 2.8 (does not happen in 2.9)

of the S_SEGMENTs were not all the same, the specctra PATH points would 
come out wrong.

Fixed a bug in search function in Eeschema: search for a component reference in a complex hierarchy was broken

Pcbnew: Fixed an issue in GERBER file creation, under Vista and W7 only for non administrator users
Plot files were 0 byte length.
This was due to use of function tmpfile() in a GERBER function to create a temporary file that seems not working using mingw.
Replaced by more usual files functions.

Eeschema: fixed some issues in undo/redo and ESC commands related to hierarchical sheets; Work in progress

Grid list display in popup menu: go back to the previous version, due to problems when using tabs in this menu.

fixed very minor bugs.

Build BOM: in one part per line, fields are now selectable (like others formats)

* Some bugs fixed
* Starting enhancements in Libedit: menubar and commands to "plot" current component in PNG or SVF file (SVG file not fully working, must be refined)

output 8 user fields

* Replaced find dialog with wxFormBuilder version.
* New find dialog is modeless, supports more advanced search features,
  remembers it's last position, size, search history, and search settings,
  and implements initial support for replacing.
* Added Shift+F5 hot key to search for next DRC marker.  F5 now just
  repeats previous search.
* Minor cosmetic enhancements to label edit dialog.
* Remove tab from grid size text printf to fix toolbar grid combobox
  display in wxGTK.
* Updated my TODO list items.