Options --dirname-pattern and --filename-pattern

Instaloader downloads all posts in

  <DIRNAME>/<FILENAME>+(suffix and extension)

which are now generated by the templates given with --dirname-pattern
and --filename-pattern. These templates may contain specifiers such as
'{target}', '{profile}', '{date}' and '{shortcode}'.

Default for --dirname-pattern is '{target}', default for
--filename-pattern is '{date:%Y-%m-%d_%H-%M-%S}'

The former options --no-profile-subdir and --hashtag-username were
removed, because their behavior can now be achieved like this:

--no-profile-subdir and --hashtag-username:
--dirname-pattern='.' --filename-pattern='{profile}__{date:%Y-%m-%d_%H-%M-%S}'

--no-profile-subdir, but not --hashtag-username:
--dirname-pattern='.' --filename-pattern='{target}__{date:%Y-%m-%d_%H-%M-%S}'

--hashtag-username but not --no-profile-subdir:
--dirname-pattern='{profile}'

This adds the option proposed in #23, to encode both the hashtag and the
profile name in the file's path when downloading by hashtag, e.g.:
--dirname-pattern='{target}' --filename-pattern='{profile}_{date:%Y-%m-%d_%H-%M-%S}'

(Closes #23)

.travis.yml

@@ -9,4 +9,4 @@ python:
 install:
  - pip install pylint requests
 script:
- - python3 -m pylint -r n -d bad-whitespace,missing-docstring,too-many-arguments,locally-disabled,line-too-long,too-many-public-methods,too-many-lines instaloader
+ - python3 -m pylint -r n -d bad-whitespace,missing-docstring,too-many-arguments,locally-disabled,line-too-long,too-many-public-methods,too-many-lines,too-many-instance-attributes instaloader

README.rst

@@ -157,15 +157,19 @@ Instaloader to login.
 How to Download
 ^^^^^^^^^^^^^^^
 
---no-profile-subdir        Instead of creating a subdirectory for each profile
-                           and storing pictures there, store pictures in files
-                           named ``PROFILE__DATE_TIME.jpg``.
---hashtag-username         Lookup username of pictures when downloading by
-                           #hashtag and encode it in the downlaoded file's path
-                           or filename (if ``--no-profile-subdir``). Without this
-                           option, the #hashtag is used instead. This requires an
-                           additional request to the Instagram server for each
-                           picture, which is why it is disabled by default.
+--dirname-pattern DIRNAME_PATTERN
+                           Name of directory where to store posts. {profile}
+                           is replaced by the profile name, {target} is replaced
+                           by the target you specified, i.e. either :feed,
+                           #hashtag or the profile name. Defaults to '{target}'.
+--filename-pattern FILENAME_PATTERN
+                           Prefix of filenames. Posts are stored in the
+                           directory whose pattern is given with --dirname-pattern.
+                           {profile} is replaced by the profile name,
+                           {target} is replaced by the target you specified, i.e.
+                           either :feed, #hashtag or the profile name. Also, the
+                           fields date and shortcode can be specified. Defaults
+                           to '{date:%Y-%m-%d_%H-%M-%S}'.
 --user-agent USER_AGENT    User Agent to use for HTTP requests. Per default,
                            Instaloader pretends being Chrome/51.
 --no-sleep                 Do not sleep between requests to Instagram's servers.