v1.8.0 (#105)

## Change log
  
- Youtube support added
- Custom filenames feature added
- Custom folder structure feature added
- Unsaving downloaded posts option added
- Remove duplicate posts on different subreddits option added
- Skipping given domains option added
- Keeping track of already downloaded posts on a separate file option added (See --dowloaded-posts in README)
- No audio on v.redd.it videos bug fixed (see README for details about ffmpeg)
- --default-directory option is added
- --default-options is added
- --use-local-config option is added
- Bug fixes

src/store.py

@@ -0,0 +1,24 @@
+from os import path
+
+class Store:
+    def __init__(self,directory=None):
+        self.directory = directory
+        if self.directory:
+            if path.exists(directory):
+                with open(directory, 'r') as f:
+                    self.list = f.read().split("\n")
+            else:
+                with open(self.directory, 'a'):
+                    pass
+                self.list = []
+        else:
+            self.list = []
+
+    def __call__(self):
+        return self.list
+
+    def add(self, filehash):
+        self.list.append(filehash)
+        if self.directory:
+            with open(self.directory, 'a') as f:
+                f.write("{filehash}\n".format(filehash=filehash))