Fix #1080 -- Make `nikola init` ask for stuff.

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>
fix the testsuite

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>
make `nikola init -d` work (alias for `--demo`)

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>
µchanges to coverage

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>
flake8

Signed-off-by: Chris “Kwpolska” Warrick <kwpolska@gmail.com>