px_romfs_pruner.py: PEP8ify and whitespace

- Changed from 8 spaces indent back to 4 which I find appropriate for
  Python.
- Fixed linelength to 80 chars.

Tools/px_romfs_pruner.py

 #!/usr/bin/env python
 ############################################################################
 #
-#   Copyright (C) 2014 PX4 Development Team. All rights reserved.
-#   Author: Julian Oes <joes@student.ethz.ch>
+#   Copyright (C) 2014-2015 PX4 Development Team. All rights reserved.
 
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -37,49 +36,53 @@
 """
 px_romfs_pruner.py:
 Delete all comments and newlines before ROMFS is converted to an image
+
+@author: Julian Oes <julian@oes.ch>
 """
 
 from __future__ import print_function
-import argparse, re
+import argparse
+import re
 import os
 
 
 def main():
+    # Parse commandline arguments
+    parser = argparse.ArgumentParser(description="ROMFS pruner.")
+    parser.add_argument('--folder', action="store",
+                        help="ROMFS scratch folder.")
+    args = parser.parse_args()
 
-        # Parse commandline arguments
-        parser = argparse.ArgumentParser(description="ROMFS pruner.")
-        parser.add_argument('--folder', action="store", help="ROMFS scratch folder.")
-        args = parser.parse_args()
-
-        print("Pruning ROMFS files.")
-
-        # go through
-        for (root, dirs, files) in os.walk(args.folder):
-                for file in files:
-                        # only prune text files
-                        if ".zip" in file or ".bin" in file or ".swp" in file or ".data" in file or \
-                                        ".DS_Store" in file or file.startswith("."):
-                                continue
+    print("Pruning ROMFS files.")
 
-                        file_path = os.path.join(root, file)
+    # go through
+    for (root, dirs, files) in os.walk(args.folder):
+        for file in files:
+            # only prune text files
+            if ".zip" in file or ".bin" in file or ".swp" in file \
+                    or ".data" in file or ".DS_Store" in file \
+                    or file.startswith("."):
+                continue
 
-                        # read file line by line
-                        pruned_content = ""
-                        with open(file_path, "rU") as f:
-                                for line in f:
+                file_path = os.path.join(root, file)
 
-                                        # handle mixer files differently than startup files
-                                        if file_path.endswith(".mix"):
-                                                if line.startswith(("Z:", "M:", "R: ", "O:", "S:")):
-                                                        pruned_content += line
-                                        else:
-                                                if not line.isspace() and not line.strip().startswith("#"):
-                                                        pruned_content += line
-                       # overwrite old scratch file
-                        with open(file_path, "wb") as f:
-                                pruned_content = re.sub("\r\n", "\n", pruned_content)
-                                f.write(pruned_content.encode("ascii", errors='strict'))
+                # read file line by line
+                pruned_content = ""
+                with open(file_path, "rU") as f:
+                    for line in f:
+                        # handle mixer files differently than startup files
+                        if file_path.endswith(".mix"):
+                            if line.startswith(("Z:", "M:", "R: ", "O:", "S:")):
+                                                pruned_content += line
+                        else:
+                            if not line.isspace() \
+                                    and not line.strip().startswith("#"):
+                                pruned_content += line
+                # overwrite old scratch file
+                with open(file_path, "wb") as f:
+                    pruned_content = re.sub("\r\n", "\n", pruned_content)
+                    f.write(pruned_content.encode("ascii", errors='strict'))
 
 
 if __name__ == '__main__':
-        main()
+    main()