app-shells: add oh-my-zsh
app-shells: add oh-my-zsh-powerline-theme
x11-themes: add faience-icon-theme
x11-themes: add gtk-theme-elementary
sys-fs: add ncdu
dev-go: add codegangsta-cli
dev-go: add exercism-cli
dev-python: add gmpy2
dev-python: add mpmath