Embed favicons into the result file

Modify embed_favicon.py to pass HTML file name (or use
bin/FC_pregmod.html by default) to embed favicon into. An HTML
header for the story format was replaced by a format.js file, and
therefore we can't embed favicon there anymore, hence we switch
over to the story file itself.

Closes #461.

devTools/embed_favicon.py

 #!/usr/bin/env python3
 
 '''
-Script for embedding favicons into the SugarCube Header.
+Script for embedding favicons into a HTML Header.
 
 Script file is expected to reside in devTools directory.
 
 Note: This does not actually check the image file's contents for size detection.
 
 Usage:
-python3 embed_favicon.py
+python3 embed_favicon.py [FC_pregmod.html]
 '''
 
 import sys
@@ -22,22 +22,28 @@ ext2mimetype = {
     '.ico': 'image/x-icon'
 }
 
+
 # reads a file, turns it into a data uri
 def data_uri_from_file(filename, mimetype):
-    data = open(filename,'rb').read()
+    data = open(filename, 'rb').read()
     base64data = base64.b64encode(data).decode('ascii')
-    out = 'data:%s;base64,%s'%(mimetype, base64data)
+    out = 'data:%s;base64,%s' % (mimetype, base64data)
     return out
 
+
 if __name__ == "__main__":
     # find project root directory path
     # (script file is expected to reside in devTools)
     project_root_path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-    # path to SugarCube's header.html
-    header_html_path = os.path.join(
-        project_root_path,
-        'devTools/tweeGo/storyFormats/sugarcube-2/header.html'
-    )
+    html_path = ''
+    if (len(sys.argv) > 1):
+        html_path = sys.argv[1]
+    else:
+        # path to bin/FC_pregmod.html
+        html_path = os.path.join(
+            project_root_path,
+            'bin/FC_pregmod.html'
+        )
     # path to directory containing all favicons to embed
     favicons_source_path = os.path.join(
         project_root_path,
@@ -45,18 +51,19 @@ if __name__ == "__main__":
     )
     # walk directory for all files
     favicons_paths = [
-    os.path.join(dirpath, filename) 
-    for dirpath, dirnames, filenames in os.walk(favicons_source_path) 
-    for filename in filenames
+        os.path.join(dirpath, filename)
+        for dirpath, dirnames, filenames in os.walk(favicons_source_path)
+        for filename in filenames
     ]
     # ignore files with unknown extensions
-    favicons_paths = [f for f in favicons_paths if f[-4:] in ext2mimetype.keys()]
-    
+    favicons_paths = [f for f in favicons_paths
+                      if f[-4:] in ext2mimetype.keys()]
+
     # prepare embedded data
     size_from_filename = re.compile(r'([0-9]+)\....$')
     favicons_html = []
     for fp in favicons_paths:
-        print('Found favicon source file "%s".'%(fp))
+        print('Found favicon source file "%s".' % (fp))
         # get mimetype by file extension
         mimetype = ext2mimetype[fp[-4:]]
         if (mimetype == 'image/x-icon'):
@@ -65,19 +72,19 @@ if __name__ == "__main__":
         else:
             # guess icon size from file name
             size = size_from_filename.search(fp).group(1)
-            sizes = '%sx%s'%(size, size)
+            sizes = '%sx%s' % (size, size)
         data = data_uri_from_file(fp, mimetype)
         favicons_html.append(
             # prepare html with favicon data embedded
-            '<link rel="icon" type="%s" sizes="%s" href="%s">\n'%(
+            '<link rel="icon" type="%s" sizes="%s" href="%s">\n' % (
                 mimetype, sizes, data
             )
         )
 
     # modify header file
-    with open(header_html_path,'r+',encoding='utf-8') as hf:
-        print('Rewriting "%s"...'%(header_html_path))
-        lines_in = hf.readlines() # read whole file
+    with open(html_path, 'r+', encoding='utf-8') as hf:
+        print('Rewriting "%s"...' % (html_path))
+        lines_in = hf.readlines()  # read whole file
         lines_out = []
         for line in lines_in:
             # embed favicons into head
@@ -86,8 +93,8 @@ if __name__ == "__main__":
             # remove all currently embedded favicons
             if (not (line.startswith('<link') and 'icon' in line)):
                 lines_out.append(line)
-        hf.seek(0) # move to beginning of file
-        hf.write(''.join(lines_out)) # overwrite with new data
-        hf.truncate() # remove trailing old data
-        
+        hf.seek(0)  # move to beginning of file
+        hf.write(''.join(lines_out))  # overwrite with new data
+        hf.truncate()  # remove trailing old data
+
     print('Finished.')