app: copy the new GEGL property keys in gimp_param_spec_duplicate()
app: sync the op with the drawable/image/gimp in GimpOperationTool

which currently means setting FG/BG color on properties with the
right GEGL property keys, and the output size of source ops.
app: make the chain and coordinate picking depend on GEGL property keys
app: follow GEGL propertiy keys convention change

and clean up the magic a bit.
app: fix x/y copy-paste confusion in last commit
app: GimpOperationTool: don't crash GimpGeglTool
app: add a default impl of GimpImageMapTool::reset()

and chain up where possible instead of duplicating that code.
app: GimpOperationTool sync the op with drawable/context in reset()
app: GimpOperationTool: change values for color roles property keys

Foreground and background are GIMP concepts; the annotations on GEGL ops
should be about how the operation makes use of the meta-data; not where
it comes from in one particular application using GEGL.

old names:

"role", "foreground-color",
"role", "background-color",

new names:
"role", "color-primary",
"role", "color-secondary",
file-gif-save2 takes 3 more params.
No tabs please, we're British.
app: the icon's name is format-text-strikethrough not format-edit-strikethrough
app_ don't symlink the test icon theme on windows, there is no symlink()
app: add gegl:tile-glass to Filters -> Artistic
plug-ins, pdb: remove the tile-glass plug-in and add a PDB compat procedure
app: add gegl:tile-glass to the checks in sanity.c
app: don't serialize GEGL properties that are auto-synced with the image
app: add gegl:perlin-noise and gegl:simplex-noise to Filters->Render->Clouds
app: add gegl:panorama-projection to Filters -> Map
pygimp: move histogram-export to Colors -> Info