Adaptor - Handle font style correctly in the font controller.

Adaptor - Handle font style correctly in the font controller.

[problem]      The font controller always retrieves a 'Regular' font style if no font name is given,
               even if a different font style is set (ex: Light) and a valid font for this style exists.
[cause]        If no font name is given, the font controller resets the style to default (which is Regular) as well.
               In general the font controller doesn't handle the font style completely.
[solution]     Fix the handle on font styles inside the font controller.

Change-Id: I879ae3c12d88b32f51ce9c00d667a4948933f2a1
Signed-off-by: Victor Cebollada <v.cebollada@samsung.com>
Signed-off-by: Adeel Kazmi <adeel.kazmi@samsung.com>