Tasks to be executed

Load state.env['tasks'] from arguments
Tasks to be executed : Initialize env.tasks

Initialize 'env.tasks' to empty list.
Tasks to be executed : Doc for env.tasks
Tasks to be executed : Changelog
Use task variable name when task name is undefined.

In fabric.main.extract_tasks(), the dict mapping names to new-style task
objects now uses the variable name of the object when the object's name
attribute is not defined.  (Technically, when not obj.name or obj.name
== 'undefined').

This change brings the behavior for mapping tasks to names in compliance
with the fabric documentation.
http://docs.fabfile.org/en/1.4.3/usage/tasks.html#new-style-tasks:

    Subclass Task (Task itself is intended to be abstract), define a run
    method, and instantiate your subclass at module level.  Instances’
    name attributes are used as the task name; if omitted the instance’s
    variable name will be used instead.

A test case was added to confirm that the task name equal the variable
name when the task object name attribute is undefined.  This test fails
with the old code and passes with the patched code.
Added issue #766 note to the changelog.
Issue-766 Add name attribute to tasks without one.

New-style Task subclass objects which do not define a name attribute end
up with the default obj.name = 'undefined' from Task.  When the tasks
are extracted from a loaded fabfile, obj.name should be set to the name
of the instance variable, since obj.name is used internally by fabric in
some circumstances, e.g. when `execute()` is called.  This commit sets
`obj.name = name` for task objects without a name, or with an undefined
name.
Merge branch '1.5'
Merge pull request #709 from rsaikali/master

List of tasks to be executed

Conflicts:
	docs/changelog.rst
Formatting tweaks
Add link to env var docs in CL entry
Changelog format tweak
Update LICENSE date, hurr
Merge branch '1.5'
Make dev-Paramiko requirement for dev-Fab super explicit
Merge branch '1.5'
Big ole roadmap overhaul
Add example of `execute` host lookup combo tasks
Add FAQ link & counterexample
Merge branch '1.5'

Conflicts:
	docs/roadmap.rst