Also, another way to fill in the gaps is to select one of the vertices (the one you wish to remain where it is) and press shift S choose the option "Cursor to Selection" then select the vertex you wish to move and press shift s again, this time choosing "Selection to Cursor" this will cause the vertices to snap together, at which point you can just remove the double, and it will join the two edges into one single one.
I saw a video, which I can't find, and was going to see if there was a plugin that did the same thing. I can't remember what the method was called, but it was just like draw a circle and it balloons out, what is that called? Parametric, Volumetric, Pantogram or another name?
Better to have loved and lost than never to have loved at all