Reorganize view code.

Reorganize view code.

Replace most of the view closures with external 
private functions.
This has several good side effects in my opinion:
- view functions are shorter;
- we know which objects are used for each callback
  function, because we need to explicitly pass them
  as arguments;
- external functions can be reused by multiple views
  if required (and we have the _use example here);
- if an external callback become less straightforward,
  it is now possible to directly unit test it.

Tests: `make check`.

QA:
If unit tests pass we have some confidence that
the interactive session is not broken.
However, some time spent on it would be great,
creating/editing/destroying environments, setting
them as default, canceling the changes, starting
one of them, etc...
Thanks a lot.

https://code.launchpad.net/~frankban/juju-quickstart/no-closure-for-you/+merge/245868

(do not edit description out of merge proposal)

[frankban, 2015-01-08 14:53:46]

Please take a look.

[matthew.scott, 2015-01-08 17:43:32]

LGTM, no QA yet (if bac doesn't get to it, I can do it later in the day)

[bac, 2015-01-08 18:32:47]

LGTM. WIll QA now.

[bac, 2015-01-08 19:21:29]

QA was OK.

I changed defaults, created a new environment, and launched a local env.

[frankban, 2015-01-12 08:32:54]

*** Submitted:

Reorganize view code.

Replace most of the view closures with external 
private functions.
This has several good side effects in my opinion:
- view functions are shorter;
- we know which objects are used for each callback
  function, because we need to explicitly pass them
  as arguments;
- external functions can be reused by multiple views
  if required (and we have the _use example here);
- if an external callback become less straightforward,
  it is now possible to directly unit test it.

Tests: `make check`.

QA:
If unit tests pass we have some confidence that
the interactive session is not broken.
However, some time spent on it would be great,
creating/editing/destroying environments, setting
them as default, canceling the changes, starting
one of them, etc...
Thanks a lot.

R=matthew.scott, bac
CC=
https://codereview.appspot.com/194080043

[frankban, 2015-01-12 08:34:31]

Thank you both for the reviews!