Switch to pure python pyScss from libsass (no need in C++ on Windows)

requirements.txt

@@ -2,6 +2,7 @@
  algorithm==1.0.0
  dependency_injection==1.1.0
  filesystem_tree==1.0.1
+ first==2.0.1
  python-mimeparse==0.1.4
 aspen==0.42
 
@@ -16,7 +17,8 @@ mistune_contrib==0.1
 
 honcho==0.5.0
 
- six==1.10.0
-libsass==0.3.0
+ enum34==1.1.6
+ pathlib==1.0.1
+pyScss==1.3.5
 
 --editable .

www/assets/%version/inside.gratipay.css.spt

@@ -1,11 +1,11 @@
 import os
-import sass
+import scss
 
 filename = os.path.join(website.project_root, 'scss', 'inside.gratipay.scss')
 output_style = 'compressed' if website.compress_assets else 'nested'
 cache = os.environ.get('INSIDE_GRATIPAY_CACHE_CSS', '')
 [---]
-css = sass.compile(output_style=str(output_style),filename=str(filename))
+css = scss.compiler.compile_file(filename, output_style=output_style)
 if cache:
     response.headers['Expires'] = 'Sun, 17 Jan 2038 19:14:07 GMT'
 [---] via jinja2