Fix window position and size issue in low resolution.

Fix window position and size issue in low resolution.

[Problem] When opening in low resolution the window border is positioned on the left side not centered and window size is not properly adjusted according to resolution.

[Cause & Measure]
 Cause : Window size and position isn't properly initialized and inside CustomBorder Constructor, MinSize is set to default value.
 Measure : Window size, position and  MinSize is properly calculated according to screen size.

Change-Id: Ife04002276ae819f8314dcdc3b740f5f606ed9db
Signed-off-by: Md. Farhan Mahtab/NC eXperience Group /SRBD/Engineer/Samsung Electronics <farhan.m1@samsung.com>