Roll back the clock to 1980 and Greater Houston looks quite a bit different.Some of the tall buildings, meandering toll roads and shiny professional sports venues aren't there, of course, but of more significance is the absence of many places that Houstonians now call home. As the metro area's population doubled over the past three decades, extensive developments and master-planned communities popped up or expanded to serve those with the means to buy spanking new homes on the suburban fringe. As for those of little means - many of them immigrants, legal and otherwise - they increasingly crowded into older,...