Updated `libsite.sh': new, fix, clean

New:

    Added new VAULT option for `core:requires'.

Fix:

    Issue with disabled modules still showing up in usage fixed.

    Allow public functions with periods in their name.

Cleanup:

    Updated `Makefile': install `log' and `tmp'  under `var'.

    Added named variables for import error codes.

    Set the arbitrary error codes to 128..255 rather than the
    more ambiguous 0..127 range.
Updated `examples/site.conf.eg': disabled modules

Some modules have been disabled by default as their use is not
expected to be wide-spread amongst the general user.
Updated `module/cpf': added `HAS_AUTOED' theme option
Updated `module/unit': fix, update, cosmetic

Enable all modules before unit tests commence.

Fixed a small reporting issue.
Updated `module/remote': clean

Dependency on `module/ldap' removed; this module no longer (directly
at least) depends on the ldap module.

The `.eval()' suffix cleanup applied.
Updated `module/hgd': graceful degredation
Unit test for `hgd' updated
Updated `module/util': encapsulated `jsontool'
Unit test for `util' updated
Updated `module/gpg': clean
Updated `module/net': new, clean

New:

    :net:localportping() - for checking if a local tcp port is open or
    not without using a client (but using netstat instead).

    :net:freelocalport() - for finding free local ports to bind to,
    optionally taking a list of preferred ports to check first.

Cleanup:

    General cleanup.
Updated `module/ng': clean
Updated `module/vault': new, clean

The public `read()' function was split up into public and internal.

Unit test for the new private function added.

Cosmetic rearrangement of code.
Updated python code to align with vault module
Updated `libexec/softlayer': flag for cache added

Added a programatic flag (variable) to enable/disable caching, and
set that to false as softlayer API calls are not too costly.
New `module/softlayer'

New site module that interfaces with `extern/softlayer'.
New `module/mongo'
New `module/tunnel'
New `module/pagerduty'
Added `module/tunnel' unit tests: closes nima/site#18