`satis build` always scan all repositories.

Slightly related to #94 , but to me it feels like an actual bug.
Every time `satis build …` is invoked, it always scan all repositories regardless of command line specs.
Even if you specify just one project to rebuild, all listed repositories will be accessed every time, making the ability to specify packages to rebuild largely useless.

For those interested, the problem starts around `src/Console/Command/BuildCommand.php:183`

Start by reading src/Console/Command/BuildCommand.php around line 183 and trace how command-line package specifications are handled during `satis build`. Reproduce a build targeting one project and verify that repositories outside the requested specs are not accessed; done means targeted builds no longer scan every listed repository.

Written by the indexing model from the issue text.