Add method to prefix following calls to transport

[reaktivo]

Added method to solve the problem of needing to prefix calls to transport with another function. You can now do this:

transport.chdir(path, function() {
  transport.git('pull');
  transport.npm('install');
});

which would be the same as calling

transport.exec('cd my-path && git pull');
transport.exec('cd my-path && npm install');

Fixes #2

[pstadler]

Thanks for your effort.

There are a couple of things that I want to further investigate regarding interactive shells. Besides that I have a similar solution which I didn't push yet:

transport.with(cmd|options[, options], fn);

// Example 1:
transport.with('cd foo', fn); // prepend 'cd foo && ' to commands inside fn
// Example 2:
transport.with({silent: true}, fn); // commands inside fn are executed with silent=true
// Example 3:
transport.with('cd foo', {silent: true}, fn); // 1+2 together

The code works, but I'm holding it back until I figured out how the logging should work inside these blocks and if this makes sense at all.

What do you think?

[reaktivo]

I think your solution is a lot more elegant. I hope it does get merged. The documentation should just be explicit about the behaviour in the case that the exec calls inside the with fn get called with their own options. Also, for clarity, I feel it's the best to have the log actually log the complete command including the "prefix"