Merge tag 'v5.1.0C' into develop

syncplaces-5.1.0C-sm+fx.xpi
ref #3: add 5.1.0{B,C} SHA1 sums
Merge tag 'v5.1.0D' into develop

syncplaces-5.1.0D.xpi
Fixed PlacesUtils.getCharsetForURI, kept the deprecated function for older versions of Firefox.