Issue #8 : main activity with buttons and custom style.

Signed-off-by: Ah-Lun Tang <tang@ahlun.be>
Issue #8: portrait mode for home activity

Signed-off-by: Ah-Lun Tang <tang@ahlun.be>
Issue #8 : unifying button style properties.

Signed-off-by: Ah-Lun Tang <tang@ahlun.be>