This commit allows to specify arrays in [group:vars] block.

Signed-off-by: Oleg Bulatov <oleg@bulatov.me>

This prevents a traceback when the group is empty.
Fixes #6258

Post merging of GH-5837 via GH-5749.

closes #5749

Conflicts:
	test/units/TestInventory.py

tests issue #5749
 same host defined in different groups which in turn are defined
 in different ini files in an inventory directory

Conflicts:
	test/units/TestInventory.py

0. Uncomment the test.
1. Test fails.
2. Make vars unique per file in test inventory files.
3. Modify token addition to not ast.literal_eval(v) a variable containing a hash.
4. Modify vars to have an escape in test inventory file.
5. Catch exceptions explicitly. Any unknown exceptions should be a bug.
6. Test passes.

This reverts commit a8082874, reversing
changes made to 6129ea75.

closes #5749

Conflicts:
	test/units/TestInventory.py

tests issue #5749
 same host defined in different groups which in turn are defined
 in different ini files in an inventory directory

Conflicts:
	test/units/TestInventory.py

It came up that fixing this unit test may relate to another ticket that is open. This work allows us to uncomment this unit test by fixing how we pars variables allowing a quoted variable to contain a '#'.

Work also went into cleaning up some of the test data to clarify what was working.

Lastly work went into cleaning up formatting so that the code is easily read.

This prevents a traceback when the group is empty.
Fixes #6258

Also added a new test (test_subset_range) for future validation.

Fixes #4620

port parsing errors
Fixes problesm introduced by 948d019f
Adds testcases to defend

Return inventory objects in the order they are presented.  Additionally, fix host slicing such that it works on Python terms with
zero indexed lists and a non-inclusive final element.

Instantiating the Inventory class with host_list=None now results in an
empty inventory instead of an error.

covered to 100%

and ipv6 addresses.

If someone has a " #" in a quoted var string, it
will interpret that as a comment and refuse to
load the inventory file due to an unbalanced
quote. Noisy failure > unexpected behavior.

when defining group variables

This allows patterns such as webservers:!debian:&datacenter1 to target
hosts in the webservers group, that are not in the debian group, but are
in the datacenter1 group. It also parses patterns left to right.

  - Code, docs, tests.
  - Also added test of large range 000-142 to verify alpha range did not
    break this.

page.