update README

README

@@ -7,19 +7,27 @@ The git repository can be found at:
 
 https://github.com/slyrus/retrospectiff
 
-There is currently no documentation, no website and no examples. But,
-to get started, check out the read-tiff-file function.
+See the test directory for examples of using the read-tiff-file and
+write-tiff-file functions.
 
-(defparameter *snow-image* (read-tiff-file "images/snow.tiff"))
+The following types of images can be read and written:
 
-Currently, only a small subset of TIFF images are supported, but it
-can read 8-bit RGB and ARGB images in both uncompressed form and LZW
-compressed form.
+* bitmap images
+* grayscale images (8 or 4-bits per pixel)
+* RGB, and ARGB images (8- or 16-bits per pixel)
+
+The following compression schemes are supported:
+
+* None (uncompressed images)
+* LZW
+* packbits
+* deflate (read only)
+* JPEG (read only)
 
 Planned features include:
 
- * Reading grayscale images
- * Reading 4- and 16-bit-per-sample images
  * Writing more formats of TIFF images
  * Performance enhancements
 
+For additional examples of using the retrospectiff API, check out the
+opticl <http://github.com/slyrus/opticl> library.