destination coordinates, and whether they are in pixels/map coordinates

And make some TODO notes flagging errors identified along the way

… issues when a second raster is loaded into the georeferencer

…ults in incorrect placement of source points

…y complicates the code

…points must ALWAYS be in source layer coordinates

raster file name for these and not the output raster file name

The GCPs relate specifically to the ORIGINAL image, not the warped
output exported after georeferencing. If we use the output file
name for the .points file then when THIS georeferenced output is
loaded into the georeferencer we get misleading location of
source GCP points, as the pixel coordinates are from the ORIGINAL
image, not the warped one.

…images

from class which stores graphical item representing point

This is too fragile, there's too many different situations which
should lead us to invalidate the cached point which are not
being caught.

are disabled

points instead of always using source pixel row/columns

The "always use pixels" approach does not work well when a source
image already has some georeferencing information attached.

Also add tests for this, and fix loading of "enabled" status for
points when loading points from a file

enabled

And partially fix this functionality when using an already
georeferenced image (not fully)

(cherry picked from commit 74d7e13)

(cherry picked from commit 23402c8)

(cherry picked from commit d76fe79)

(cherry picked from commit 977585c)

points don't move on canvas when edited in list

(cherry picked from commit ca2dbef)

points in table are always updated to reflect actual target CRS
whenever it is changed

(cherry picked from commit 15d7c8a)

(cherry picked from commit 610a0a6)

(cherry picked from commit a2bb366)

georeferenced, assume the source points are in the
raster's IF there's no explicit crs information in the .points file

(cherry picked from commit 8a12a0b)

(cherry picked from commit feaa954)

(cherry picked from commit a39ed7b)

set CRS of destination to match the georeference target CRS

(cherry picked from commit 90c1325)

(cherry picked from commit 93564e0)

Helps clarify for users exactly what CRS these destination coordinates
are in

(cherry picked from commit 622c120)

(cherry picked from commit 27db775)

(cherry picked from commit 4877003)

(cherry picked from commit 4e035e6)