Avoid walking off the layer group string in ParseGroupString

Oops - fix bug introduced in previous commit
Remove function GetGroupOfLayer, use GetLayerGroupNumberByNumber() instead.

These functions are virtually identical, the only difference being special-case
handling in the deleted function to force returning max_group if passed layer
number "max_copper_layer".

This actually (as it happens), corresponds to the bottom silk layer, and this
handling is suspect at best. GetLayerGroupNumberByNumber() will return the
group corresponding to the bottom of the board (whichever that may be).
constify name argument to ghid_notebook_page()

Avoids a compiler warning when building the GTK hid.
hid/gerber: Fix broken eagle-suffix filename assignemnt

This was broken carelessly in commit c812fbae2dfe74cd3d39dd2dcc5cdbb08e07555a

NB: Please pay attention to compiler warnings... they are there for a reason!
hid/gtk: Don't use a static local variable for the tooltip id, it is ugly.
hid/gcode: Don't use PCB->Extent{Min,Max}{X,Y}.. they are about to be killed

The extent updating code is broken, and adds yet more special-case code which
handles the "outline" layer. Use PCB->MaxWidth and PCB->MaxHeight, these
represent the size the of board, and are the values which the extents code
defaulted to if it did not find any lines on the "outline" layer.
Revert "Introduce dynamic board size."

This reverts commit d91daad65c3ea7e2e1b6ce876b7d41550f6a784e.

    The goal is to eventually define the board's extent by the outline
    layer, only. That way, all the exporters can export properly
    sized layouts.

    Undoubtly, this can also influence the GUIs. For example, "zoom to fit"
    becomes a slightly different meaning and drawing outside the board's
    extent becomes possible. Autorouting and similars can be limited to
    the actual board size. Resizing a board to the lower left no longer
    requires the error-prone moving of all the stuff and keeps file diffs
    small.

The code in question does NOT dynamically update the desired information
when the outline layer changes, and it adds yet more magic meaning to the
 "outline" layer which I'm trying slowly to remove from PCB. This is the
wrong way to cope with unlimited board sizes.
hid/*: layer_sort()  Only copper layers participate in the layer stack

Don't consider the layers greater than or equal to max_copper_layer,
ie.. Silk layers are not in the layer stack. Actually, don't even
worry about checking the layer is a copper layer - it will be.

Use GetLayerGroupNumberByNumber() directly, there is no need to worry
about being passed strange layer numbers.

Rename layer_sort() to layer_stack_sort(), reflecting our (new) preconditions.
hid/gtk: Remove debugging printf accidentally committed
action.c: Fix handling of the case where a segment already exists when drawing lines

We cancel creating any segment which would overlay an existing, but we previously
failed to move the start-point and toggle the line-start direction so as to
continue drawing from the desired point as if we HAD created the line.
Remove function SearchScreenGridSlop() and use SearchObjectByLocation() directly
Remove unused #include "setjmp.h" from a few files