Enabled gcc's automatic vectorization for the whole build

Change-Id: Idfcc7f1810605308d64667c06e2b1b823a6cee7c
compile the whole build with O3 flag

Change-Id: I92d5951a90be2ed8e69aa5f67d1f1ff60507c790
gitignore: ignore backup files(*.*~) produced by gedit

Change-Id: Ie4e59f611f8a73fbe3674f5e4c71384c5be98c46