Argh, more README tweaks [ci skip]

README.md

@@ -36,26 +36,26 @@ file format.
 
 ## Adding new formats
 
-You register a new format by calling `addformat(fmt, magic,
+You register a new format by calling `add_format(fmt, magic,
 extension)`.  `fmt` is a `DataFormat` type, most conveniently created
 as `format"IDENTIFIER"`.  `magic` typically contains the magic bytes
 that identify the format.  Here are some examples:
 
 ```jl
 # A straightforward format
-addformat(format"PNG", [0x89,0x50,0x4e,0x47,0x0d,0x0a,0x1a,0x0a], ".png")
+add_format(format"PNG", [0x89,0x50,0x4e,0x47,0x0d,0x0a,0x1a,0x0a], ".png")
 
 # A format that uses only ASCII characters in its magic bytes, and can
 # have one of two possible file extensions
-addformat(format"NRRD", "NRRD", [".nrrd",".nhdr"])
+add_format(format"NRRD", "NRRD", [".nrrd",".nhdr"])
 
 # A format whose magic bytes might not be at the beginning of the file,
 # necessitating a custom function `detecthdf5` to find them
-addformat(format"HDF5", detecthdf5, [".h5", ".hdf5"])
+add_format(format"HDF5", detecthdf5, [".h5", ".hdf5"])
 
 # A fictitious format that, unfortunately, provides no magic
 # bytes. Here we have to place our faith in the file extension.
-addformat(format"DICEY", (), ".dcy")
+add_format(format"DICEY", (), ".dcy")
 ```
 
 You can also declare that certain formats require certain packages for