Fixed cursor bug in StringPlugValueWidget continuous update mode.
Fixed cursor bug in StringPlugValueWidget continuous update mode.

It would leap to the end of the line every time a character was entered - effectively preventing editing anywhere except at the end.

Fixes #796.

appleseedhq/gaffer,GafferHQ/gaffer,hradec/gaffer,GafferHQ/gaffer,chippey/gaffer,ImageEngine/gaffer,davidsminor/gaffer,johnhaddon/gaffer,cedriclaunay/gaffer,hradec/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,boberfly/gaffer,boberfly/gaffer,chippey/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,hradec/gaffer,hradec/gaffer,ivanimanishi/gaffer,ImageEngine/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,davidsminor/gaffer,goddardl/gaffer,GafferHQ/gaffer,boberfly/gaffer,chippey/gaffer,lucienfostier/gaffer,hradec/gaffer,boberfly/gaffer,goddardl/gaffer,cedriclaunay/gaffer,cedriclaunay/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,chippey/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,cedriclaunay/gaffer,davidsminor/gaffer,lucienfostier/gaffer,davidsminor/gaffer,johnhaddon/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,lucienfostier/gaffer,goddardl/gaffer,goddardl/gaffer,andrewkaufman/gaffer,ivanimanishi/gaffer,ivanimanishi/gaffer