[3.0] Retrieve the input font's style.

[3.0] Retrieve the input font's style.

* Removes the font's style string from the InputStyle struct.
  This string is useless as it stores only the string style set
  through the property system. This string does not contain
  the valid font's style if the style changes as a consequence of
  moving the cursor.

Change-Id: I41d05f3686d949e1b50233df7f6d05fc2583af92
Signed-off-by: Victor Cebollada <v.cebollada@samsung.com>