Emmet for brackets disabling CSS browser prefixes

Emmet1 has the ability to automatically add CSS browser prefixes (vendor prefix).

For example, enter the following CSS (* to indicate the cursor position) in brackets:

div{
bgs*
Press the TAB key to expand the following,

div{
-webkit-background-size:
Background-size:

But I don't like it to claim it. I prefer to use Autoprefixer2 with Grunt.js or gulp.js to do processing, more controllable, and keep the source code clean.

So I need to disable this feature.

Emmet provides a configuration item: CSS.AUTOINSERTVENDORPREFIXES3, but under brackets, this configuration process is very tangled.
My system is openSUSE 13.1, the steps to disable are as follows:
/home/sam a new directory under the home directory Emmet (you'll have to build it somewhere else)
Adding Preferences.json files to the Emmet directory
Add the following code to the file: {"css.autoinsertvendorprefixes": false}
Open the brackets main interface of the Emmet menu, select Preferences ...
Fill in/home/sam/emmet in extension folder (cannot use ~/emmet)
Restart Brackets