Tweak package archives

Only use MELPA, js2-mode works nowadays, update package archive before
installing anything.
Disable electrict-indent-mode for Python
Use flycheck instead of flymake
fixup
Use cask
python: Disable which-function-mode

It's sloooooow.
flycheck depends on grizzl
Add packages
Remove manually installed packages
Tweak flycheck
Sort Cask
Add php-mode and web-mode