Warn about using `lexer` as a local in `jade.render()`

Using it as a local in `jade.compile()({lexer: 'blah'})` is still supported.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Update commander

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Update express

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Use default 2-space indentation for all non-string true-y values

Fixes #1755.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Merge pull request #1757 from jadejs/fix-pretty

Use default 2-space indentation for all non-string true-y values
Merge pull request #1756 from jadejs/update-deps

Update dependencies
Merge pull request #1738 from jadejs/real-lexer-warn

Warn about using `lexer` as a local in `jade.render()`
Move the `lexer` option warning so that it is always correctly outputted

[see #1738]
Release 1.8.1
Merge branch 'master' into v2