alpha reoder in synfig-core potfiles.in
add missing files in synfig-core potfiles.in

mptr_cairo_png, trgt_cairo_png, trgt_png_spritessheet, all from mod_svg, bases_types, bone
boneweightpair, cairo_operators, cairo_renddesc, filecontainer(°), filesystem(*), layer_skeleton,
layer_switch, matrix, valuenode_anglestring, valuenode_atan2, valuenode_average, valuenode_blinereversetangent,
bone(*), valuenode_derivate, valuenode_dilist, valuenode_dotproduct, valuenode_dynamic, valuenode_gradientcolor,
valuenode_greyed, valuenode_intstring, valuenode_log, valuenode_staticlist, valuenode_weightedaverage,
valueoperations, zstreambuf, weightedvalue