Added src publish property to drawer for developer to specify custom icon
Changes done to drawers.js
Changes in design made to drawer as per review comment given
Merge branch 'master' into CMB-81-rakesh25
Changes made to Drawers for applying font-icon or image icon dynamically as in IconButton
Merge branch 'master' into CMB-81-rakesh25

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Minor formatting and spacing cleanup/standardization.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Tweaked and simplified the logic for the drawer activator image/icon property.
Uses the control's ID now, doesn't store the className supports more cases of icon/image and vice versa, the ability to reset it to defaults and have it update when either icon or src changes to both be blank, simplified generated CSS.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Merge pull request #1461 from enyojs/CMB-81-rakesh25

Added src publish property to drawer for developer to specify custom icon