PyLint: Fix recognition of new lines

Since we prevent \r\r\n line breaks in the buffer (and rather return \r\n), we can also change the recognition of line breaks for the ASSERTION_ERROR_REGEXP.

lib/py_lint_adapter.rb

@@ -2,7 +2,7 @@
 
 class PyLintAdapter < TestingFrameworkAdapter
   REGEXP = %r{Your code has been rated at (-?\d+\.?\d*)/(\d+\.?\d*)}
-  ASSERTION_ERROR_REGEXP = /^(.*?\.py):(\d+):(.*?)\(([^,]*?), ([^,]*?),([^,]*?)\) ((?>.|\r|\n)*?)(?<!\r\n)\n(?!\n)/
+  ASSERTION_ERROR_REGEXP = /^(.*?\.py):(\d+):(.*?)\(([^,]*?), ([^,]*?),([^,]*?)\) ((?>.|\r|\n)*?)(?<!\r)\n(?!\n)/
 
   def self.framework_name
     'PyLint'