style: Fix PEP8 blank lines issues in Python files

Done with `autopep8 --select=E3,W3`, fixes:

- E301 - Add missing blank line.
- E302 - Add missing 2 blank lines.
- E303 - Remove extra blank lines.
- E304 - Remove blank line following function decorator.
- E309 - Add missing blank line.
- W391 - Remove trailing blank lines.

platform/javascript/detect.py

@@ -2,12 +2,15 @@ import os
 import sys
 import string
 
+
 def is_active():
     return True
 
+
 def get_name():
     return "JavaScript"
 
+
 def can_build():
 
     import os
@@ -15,6 +18,7 @@ def can_build():
         return False
     return True
 
+
 def get_opts():
 
     return [
@@ -22,6 +26,7 @@ def get_opts():
         ['javascript_eval', 'Enable JavaScript eval interface', 'yes'],
     ]
 
+
 def get_flags():
 
     return [
@@ -33,7 +38,6 @@ def get_flags():
     ]
 
 
-
 def configure(env):
     env['ENV'] = os.environ;
     env.use_windows_spawn_fix('javascript')