Revert "More pip dependancy. Keep qt with system package, more fast to install."
Prefer to use debian dependancy, more faster for travis. Wait new cache pip feature.
This reverts commit 600033de6f182bad6fd360faae4e1b49252de38d.

Conflicts:
	.travis.yml
	INSTALL.md
	requirements.txt
test: remove filter GaussianBlur, opencv 2.3 don't like him.