Change the few scripts to normal Enrico tools

[cdeil]

Currently we have three "scripts" (see here and here) and a lot of "tools" (see here and here).

I think we should change the "scripts" to "tools", i.e. put them into the bin folder and have their name start with enrico_. I realise they are a little bit different because they have extra dependencies, but I don't think that's a problem ... we'll simply print "you need to install X to run this tool" when it's not available.

The advantage of making the change is that it's a bit easier for the user (enrico and tab-complete shows all tools / scripts available and no need to wonder what the distinction is when reading the docs).

@davidsanchez OK if I make this change?