Re #6308. Add a .gitattributes file setting the new 'text' attribute

From git 1.7.2, there's a new way of dealing with line endings.
This setting of the attribute should mean that developers get their
native line endings locally, but that we only get LF endings in the repo.
Requiring everyone to set a config property to enforce this should
no longer be necessary.

.gitattributes

@@ -0,0 +1,4 @@
+# Set default behaviour, in case users don't have core.autocrlf set.
+# See https://help.github.com/articles/dealing-with-line-endings#platform-all for more info
+# N.B. Only works with git client 1.7.2+
+* text=auto

.gitignore

@@ -2,9 +2,6 @@
 
 # **** 'Personal' entries don't belong in here - put them in your .git/info/exclude file ****
 
-# Ignore gitatrributes file
-.gitattributes
-
 # Ignore text editor (e.g. emacs) autosave files
 *~