Fix compatibility issue with passlib version < 1.6 (as encountered on eg EL6 systems)

- passlib.apache.HtpasswdFile's 'default_scheme' was called 'default'
before passlib version 1.6
- while here also deal with passlib.apache.HtpasswdFile's older
'autoload' paramter vs the newer 'new' one.
fixes 4365 - Mac with cisco vpn client, GenericBsdIfconfigNetwork get_default_interfaces fails with index out of range
gc_storage rewrite commit 1
gc_storage rewrite commit 2
"touch" option on file is new in 1.4
Merge pull request #4366 from skyl/GenericBsd-get_default_interfaces

fixes 4365 - Mac with cisco vpn client, GenericBsdIfconfigNetwork get_default_interfaces fails with index out of range
replace dashes in rc.conf keys (which are based on freebsd rc.d filenames) to underscores
Adding some labels so we don't get "#id22" for the links in the docs.
ec2_ami: Account for AWS's "eventual consistency" with AMI creation.

Calling `ec2.get_image` right after `ec2.create_image` may raise error
"InvalidAMIID.NotFound". This has happend roughly 1 time out of 10 for me.

Other people has bitten by this too:
- https://github.com/Netflix/aminator/commit/5707f100a07d3432027d1e7a3305567a2a7d2574
- http://stackoverflow.com/a/14794952
- https://bitbucket.org/utoolity/bamboo-aws-plugin/pull-request/22/baws-116-fix-ec2-image-task-failing-with/diff
Merge pull request #4370 from hostage-nl/devel

replace dashes to underscores in rc.conf keys (based on freebsd rc.d filenames)
Allow specifying an alternate ec2.ini path via EC2_INI_PATH environment variable.
Allow for updating host vars in add_host
Merge pull request #4376 from cchurch/devel

Support for alternate ec2.ini path via EC2_INI_PATH environment variable
Merge pull request #4364 from stoned/pre-1.6-passlib

Fix compatibility issue with passlib version < 1.6 (as encountered on eg...
add more indexes, AWX blurb.
Add lots of anchor tags.
More exciting anchor tags, document more loop features!
More anchors!
Misc docs work.
Remove duplicate section, fix a link.