Add logging capability (#175)

* Refactoring and addition of logzero (#172)

* Refactored convert.py and added logging.

* Added logging and refactored.

* Added logzero to requirements.txt

* Added logging to metadata.py

* Created a log in misc.py. Updated slugify import.

* Some general improvement

* Improve message layout

* Improve test mechanism

* Implement debug level logging

* Fix some minor mistakes

* Make pytest happy

* Remove unimplemented --verbose option

* Update ISSUE_TEMPLATE.md

* Rename LICENSE

* Remove obvious from log.debug()

* Show track URL when writing to file (debug)

ISSUE_TEMPLATE.md

@@ -10,22 +10,23 @@ Please follow the guide below
 - [ ] [Searched](https://github.com/ritiek/spotify-downloader/issues?utf8=%E2%9C%93&q=is%3Aissue) for similar issues including closed ones
 
 #### What is the purpose of your *issue*?
-- [ ] Script won't run
-- [ ] Encountered bug
-- [ ] Feature request
+- [ ] Bug
+- [ ] Feature Request
 - [ ] Question
 - [ ] Other
 
-#### System information
-- Your `python` version: `python 3.x`
-- Your operating system: `Ubuntu 16.04`
-
 ### Description
-<!-- Provide as much information possible with relevant examples and whatever you have tried below -->
-
+<!-- Provide as much information possible and whatever you have tried below -->
 
 
+### Log
+<!-- Run the script with `--log-level=DEBUG` and paste the output below within the code block-->
+<details>
 
+```
+paste the output over here
+```
 
+</details>
 
 <!-- Give your issue a relevant title and you are good to go -->