Make get_group run in O(n*log(n)) instead of O(n^2) by using a cache (#9437 rebase)

changed local_action to alias to connection=local vs delegate_to=locahost

double the speed of loading a 10k host inventory file (#10034 rebase)

first off, we add an oddly slow basic test of 10k item inventory

Before:
```
Ran 229 tests in 13.214s

OK

real    0m13.403s
user    0m12.106s
sys 0m1.155s
```

After:
```
Ran 230 tests in 21.328s

OK

real    0m21.516s
user    0m20.099s
sys 0m1.275s
```

since that seems like a bit long for the test to add to runtime, lets profile

`python -m cProfile -s time ./bin/ansible all -i test/units/inventory_test_data/huge_range --list-hosts`

Before:
```
         1272607 function calls (1259689 primitive calls) in 8.497 seconds

   Ordered by: internal time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
    10000    4.393    0.000    4.396    0.000 __init__.py:395(_get_host)
    20000    2.695    0.000    2.697    0.000 __init__.py:341(__append_host_to_results)
    40369    0.113    0.000    0.113    0.000 {posix.lstat}
    50006    0.102    0.000    0.153    0.000 __init__.py:1490(combine_vars)
    40008    0.089    0.000    0.202    0.000 __init__.py:1546(_load_vars_from_path)
    20195    0.088    0.000    0.088    0.000 {posix.stat}
    10011    0.087    0.000    0.087    0.000 {posix.getcwd}
```

The top two lines are promising optimization targets

- populate Inventory's host cache more in _get_host, as we are looping
  over all the groups anyways.

- eliminate duplicate check of whether we've already included a host
  in the construction around __append_host_to_results we can infer
  presence of a host in the results list implies the presence of its
  name in the hostnames set, allowing us to only to the less expensive
  of the two checks

After:
```
         1252610 function calls (1239692 primitive calls) in 1.320 seconds

   Ordered by: internal time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
    40369    0.105    0.000    0.105    0.000 {posix.lstat}
    50006    0.094    0.000    0.141    0.000 __init__.py:1490(combine_vars)
    40008    0.081    0.000    0.184    0.000 __init__.py:1546(_load_vars_from_path)
    10011    0.080    0.000    0.080    0.000 {posix.getcwd}
    20195    0.074    0.000    0.074    0.000 {posix.stat}
    10002    0.069    0.000    0.261    0.000 __init__.py:1517(load_vars)
```

fixes #11998, but still leaves issue of delegate_to: localhost not working

Updates to Windows Azure inventory from Tower.  

changed check to avoid OS X broken sem_getvalue()

fixes #11988

fixes #11907

refactored the options a bit, new inventory_opts made sense to always group
fixes #7917

fixes #11979

Add become support for OpenBSD doas

fixes #11982

* Speed up serialization of hostvars by simply using the internal
  dictionary used for cached lookups
* Use blocking gets/puts on queues instead of spin locking
* Merge sequential implicitly created blocks

cloudstack: add more common returns

Fix variable name mis-match in website docs for ANSIBLE_LIBRARY. 

now passes the test of skipping list when dict attribute is undefined, added deprecation warning as this seems like bad behaviour

made sure they all look in files/vars/template dirs also when executed in play and not only from task