Add information about environment variables in Windows (#69)

README.md

@@ -64,6 +64,10 @@ Shift+right-click on empty area and open cmd and type:
 
 `"Scripts/pip.exe" install -U -r requirements.txt`
 
+- If you do not want to naviagte to your python folder from the command-line everytime you want to run the script, you can have your python 'PATH' environment variables set and then you can run the script from any directory.
+    - python install folder: like (C:\Program Files\Python36)
+    - python scripts folder: like (C:\Program Files\Python36\Scripts)
+
 ## Instructions for Downloading Songs
 
 - For all available options, run `python spotdl.py --help` (or for windows run `python.exe spotdl.py --help`).

spotdl.py

@@ -168,17 +168,11 @@ def downloadSong(content):
 
 def convertWithAvconv(music_file):
     if os.name == 'nt':
-        os.system(
-            'Scripts\\avconv.exe -loglevel 0 -i "' +
-            'Music/' +
-            music_file +
-            '.m4a" -ab 192k "' +
-            'Music/' +
-            music_file +
-            '.mp3"')
+        avconv_path = 'Scripts\\avconv.exe'
     else:
+        avconv_path = 'avconv'
     os.system(
-            'avconv -loglevel 0 -i "' +
+        avconv_path + ' -loglevel 0 -i "' +
         'Music/' +
         music_file +
         '.m4a" -ab 192k "' +