Add support for bower.json

[xaka]

I think these days bower.json is as much important as package.json and so it would totally make sense to provide status reports for bower dependencies. We probably could re-use the same status icon sliced in half for bower and npm based on whether both are in use or only one.

[nschonni]

Dupe #95

[ilanbiala]

+1

[bobbyrne01]

:+1:

[callicles]

+1

[joshuahiggins]

+1

[pine]

+1

[identy]

+1

[mstuart]

+1

[bluelnkd]

+1

[ghost]

Cross referencing alanshaw/david#34