Merge remote-tracking branch 'origin/develop' into tizen

Merge remote-tracking branch 'origin/develop' into tizen

* origin/develop:
  PROP : Refactoring CssSelectorCategory.
  DATABIND : Change the remove UX remove the X button add the del key input
  SNIPPET : Refactoring id policy
  PROP : Fix dispose exception on CssStyleTab.
  NSCREEN : Remove possible Error. Add defense code for possible error by static analyzer
  PROP : Fix exception on CssSelectorCategory.
  UIB : code refactoring for PREVENT

Conflicts:
	org.tizen.webuibuilder/src/org/tizen/webuibuilder/ui/views/databinding/SetSourceDialog.java

Change-Id: I907aafa2018d0c11de30916a26b6bd9707d32663
Signed-off-by: yonghwan82.jeon <yonghwan82.jeon@samsung.com>