Enforce LF newlines

This change is done in order to ensure that Windows users don't
encounter any newline related issues.

e.g.: Prior to this change, after the build script was run, files
from `node_modules` (having `LF` newlines, and which wouldn't have
be normalized by `git`) would be copied to the `dist/` directory
and would appear to Windows users as if they where changed.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Thanks to @XhmikosR for pointing this out!

Ref http://git-scm.com/docs/gitattributes#_effects
    http://en.wikipedia.org/wiki/Newline

Close h5bp/html5-boilerplate#1618

.gitattributes

@@ -1 +1,16 @@
+# Automatically normalize line endings for all text-based files
+# http://git-scm.com/docs/gitattributes#_effects
 * text=auto
+
+# For the following file types, normalize line endings to LF on
+# checkin and prevent conversion to CRLF when they are checked out
+# (this is required in order to prevent newline related issues like,
+# for example, after the build script is run)
+*.css   text eol=lf
+*.html  text eol=lf
+*.js    text eol=lf
+*.json  text eol=lf
+*.md    text eol=lf
+*.sh    text eol=lf
+*.txt   text eol=lf
+*.xml   text eol=lf