Add prototype repo-indexer script author_files.py.

Add:
    author_files.py
        -add prototype script to output metadata about every file in a Git
        repository: filename, author names, dates of creation and modification.
        -lacking Sphinx documentation.

bitshift/author_files.py

@@ -0,0 +1,53 @@
+"""
+Output author/date information about the latest files in a Git repository.
+
+When executed inside a Git archive, prints a single line of metadata for every
+file in the work tree. A given line contains the file's filename, authors,
+and Unix timestamps for the file's time of creation and last modification; the
+separate entries are null-delimited.
+
+Sample output:
+	socket_io.c\x00John Doe Jane Doe\x001384488690\x001384534626
+	# filename: socket_io.c
+	# Author Names:
+"""
+
+import fileinput, subprocess
+
+git_log = subprocess.check_output("git --no-pager log --name-only \
+	--pretty=format:'%n%n%an%n%at' -z", shell=True)
+
+commits = []
+for commit in git_log.split("\n\n"):
+	fields = commit.split("\n")
+	if len(fields) > 2:
+		commits.append({
+			"author" : fields[0],
+			"timestamp" : int(fields[1]),
+			"filenames" : fields[2].split("\0")[:-2]
+		})
+
+
+tracked_files = subprocess.check_output("perl -le 'for (@ARGV){ print if -f && \
+	T }' $(find . -type d -name .git -prune -o -print)", shell=True)
+tracked_files = [filename[2:] for filename in tracked_files.split("\n")[:-1]]
+
+file_authors = {}
+for commit in commits:
+	for filename in commit["filenames"]:
+		if filename in tracked_files:
+			if filename not in file_authors.keys():
+				file_authors[filename] = {
+					"authors" : [commit["author"]],
+					"timestamps" : [commit["timestamp"]]
+				}
+			else:
+				if commit["author"] not in file_authors[filename]["authors"]:
+					file_authors[filename]["authors"].append(commit["author"])
+				file_authors[filename]["timestamps"].append(commit["timestamp"])
+
+for filename in file_authors.keys():
+	authors = "\0".join(file_authors[filename]["authors"])
+	time_created = min(file_authors[filename]["timestamps"])
+	time_last_modified = max(file_authors[filename]["timestamps"])
+	print "%s\0%s\0%d\0%d" % (filename, authors, time_created, time_last_modified)