Add new option 'python_highlight_file_headers_as_comments'

The option is disabled by default and when enabled highlight shebang and
coding file headers as comments instead of special characters.

CHANGES.txt

 
     - Highlight 'import', 'from' and 'as' as include statements.
       Patch by pydave at GitHub.
+    - Added new option 'python_highlight_file_headers_as_comments' (disabled by
+      default) to highlight shebang and coding file headers as comments.
+      Proposed by pydave at GitHub.
 
 Revision 3.3.4 (2013-08-11):
 

README.rst

   Highlight doc-tests
 ``python_print_as_function``
   Highlight ``print`` statement as function for Python 2
+``python_highlight_file_headers_as_comments``
+  Highlight shebang and coding headers as comments
 ``python_highlight_all``
   Enable all the options above. *NOTE: This option don't override any
   previously set options*

syntax/python.vim

 "    python_highlight_doctests              Highlight doc-tests
 "    python_print_as_function               Highlight 'print' statement as
 "                                           function for Python 2
+"    python_highlight_file_headers_as_comments
+"                                           Highlight shebang and coding
+"                                           headers as comments
 "
 "    python_highlight_all                   Enable all the options above
 "                                           NOTE: This option don't override
 "
 
 syn match   pythonComment	"#.*$" display contains=pythonTodo,@Spell
-syn match   pythonRun		"\%^#!.*$"
-syn match   pythonCoding	"\%^.*\%(\n.*\)\?#.*coding[:=]\s*[0-9A-Za-z-_.]\+.*$"
+if !s:Enabled("g:python_highlight_file_headers_as_comments")
+  syn match   pythonRun		"\%^#!.*$"
+  syn match   pythonCoding	"\%^.*\%(\n.*\)\?#.*coding[:=]\s*[0-9A-Za-z-_.]\+.*$"
+endif
 syn keyword pythonTodo		TODO FIXME XXX contained
 
 "
   HiLink pythonDot              Normal
 
   HiLink pythonComment          Comment
-  HiLink pythonCoding           Special
-  HiLink pythonRun              Special
+  if !s:Enabled("g:python_highlight_file_headers_as_comments")
+    HiLink pythonCoding           Special
+    HiLink pythonRun              Special
+  endif
   HiLink pythonTodo             Todo
 
   HiLink pythonError            Error