Roughing out initial group description call.

I'm using erlcloud_ec2 as a basic example to follow at present and
trying to stay relatively close to what was done there.  Since
the autoscaling group record I've defined will likely need to be
operated on directly outside of this module, I'll probably move
it to an erlang_as.hrl file in the include folder shortly.
Ignore edts file.
Describe named autoscaling groups.

Proper support of named groups now.
Simple desired capacity setting operation works.

Moved the aws_autoscaling_group record into an include file as
well.  Currently no pagination nor result size support, that will
need to change next.
Cleanup per omarkj's advice.
Cleaned out imports per advice from omarkj and ypaq.

Some spacing stuff that was bugging me as well.
Some simple support for paged results from erlcloud_as:describe_groups

I'm not sure I really like the current way it's done but it's a
reasonable start.  I suspect describe_groups/4 may be overkill
or slightly ambiguous but am unsure if simply exposing a parameter
for a list as in the private describe_groups/3 is better from
an API perspective.  Opinions welcome.
Added load balancer names to autoscaling groups.

Trivial change but somebody will probably want it.
Some simplified launch configuration support.

Just description of launch configurations for now, fairly limited
set of data in the supporting record.
Roughed in autoscaling instance record and cleanup.

Functionality for building list of members, instances, etc
for queries about specific ones is all essentially the same
so also extracted that into its own function (member_params/2).
Basic autoscaling instance desciption call.

Also corrected an oversight whereby NextToken in all of the
describe calls was always being passed forwards to the actual
AWS calls as a parameter with value 'none'.  Now gets
dropped when it's 'none' via pattern matching in the function
definitions.
Can now terminate autoscaling group instances.

Also added basic autoscaling activity extraction/parsing.
Support CommonPrefixes in S3 list operations

See the S3 API docs for more information about CommonPrefixes and how
they work:

http://docs.aws.amazon.com/AmazonS3/latest/API/SOAPListBucket.html
Fixed broken version of erlcloud_cloudtrail. Reverted back to using httpc instead of lhttpc since the later doesn't work.
Added platform and product_codes attributes to return from describe_images(...)
Merge pull request #101 from campanja/add-support-for-common-prefixes

Support CommonPrefixes in S3 list operations
Added product_code and type properties to be returned from describe_images
In the previous commit I managed to overwrite a correct change. Doing it again... Added product_code and type properties to be returned from describe_images.
Changed back to use lhttpc and fixed code to not pass to content-type header parameters
Removed debug message