optimizeimages: support pngnq-s9

pngnq-s9 is essentially just a more recently dead version of pngnq,
however, due to not being able to specify multiple binary names in
the past, we've not supported it. Refactor the code to allow specifying
multiple binary names, and add pngnq-s9 to it.

overviewer_core/optimizeimages.py

@@ -20,6 +20,7 @@ import logging
 
 class Optimizer:
     binaryname = ""
+    binarynames = []
 
     def __init__(self):
         raise NotImplementedError("I can't let you do that, Dave.")
@@ -37,8 +38,13 @@ class Optimizer:
             result = filter(lambda x: os.path.exists(os.path.join(x, prog)), path)
             return len(result) != 0
 
-        if (not exists_in_path(self.binaryname)) and (not exists_in_path(self.binaryname + ".exe")):
-            raise Exception("Optimization program '%s' was not found!" % self.binaryname)
+        binaries = self.binarynames + [x + ".exe" for x in self.binarynames]
+        for b in binaries:
+            if (exists_in_path(b)):
+                self.binaryname = b
+                break
+        else:
+            raise Exception("Optimization programs '%s' were not found!" % binaries)
     
     def is_crusher(self):
         """Should return True if the optimization is lossless, i.e. none of the actual image data will be changed."""
@@ -63,7 +69,7 @@ class JPEGOptimizer:
         raise NotImplementedError("I can't let you do that, Dave.")
 
 class pngnq(NonAtomicOptimizer, PNGOptimizer):
-    binaryname = "pngnq"
+    binarynames = ["pngnq-s9", "pngnq"]
 
     def __init__(self, sampling=3, dither="n"):
         if sampling < 1 or sampling > 10:
@@ -93,7 +99,7 @@ class pngnq(NonAtomicOptimizer, PNGOptimizer):
         return False
 
 class pngcrush(NonAtomicOptimizer, PNGOptimizer):
-    binaryname = "pngcrush"
+    binarynames = ["pngcrush"]
     # really can't be bothered to add some interface for all
     # the pngcrush options, it sucks anyway
     def __init__(self, brute=False):
@@ -110,7 +116,7 @@ class pngcrush(NonAtomicOptimizer, PNGOptimizer):
         return True
 
 class optipng(Optimizer, PNGOptimizer):
-    binaryname = "optipng"
+    binarynames = ["optipng"]
 
     def __init__(self, olevel=2):
         self.olevel = olevel
@@ -122,7 +128,7 @@ class optipng(Optimizer, PNGOptimizer):
         return True
 
 class advpng(Optimizer, PNGOptimizer):
-    binaryname = "advpng"
+    binarynames = ["advpng"]
     crusher = True
 
     def __init__(self, olevel=3):
@@ -135,7 +141,7 @@ class advpng(Optimizer, PNGOptimizer):
         return True
 
 class jpegoptim(Optimizer, JPEGOptimizer):
-    binaryname = "jpegoptim"
+    binarynames = ["jpegoptim"]
     crusher = True
     quality = None
     target_size = None