Use git_submodules instead of EXTERNAL_PROJECT when BUILD_DEPS is ON

Move to submodules (#91)

Moved BUILD_DEPS path to use git submodules.

Sts provider stream leak

Fix sts provider stream leak

Fixed websocket memory leak, updated dependencies.

Update to latest deps, and pick up mqtt leak fix. (#86)

* Update to latest deps, and pick up mqtt leak fix.

* Updated mqtt version.

MQTT bug fixes, improved cmake paths for RHEL style OS builds.

Update mqtt version (#83)

* Updated deps to latest, improved cmake module searching and libdir

* Incremented version number.

signer bug fixes and api updates.

v0.6.7

Made signer take a signing config by value, made sure stream seek cle…

Windows security update

v0.6.6

Updated to latest aws-c-io to pick up a windows security fix. (#74)

Updated version string.

v0.6.5

Update version string to the tag that will be following. (#73)

Updated dependencies, added sample for non-iot-specific mqtt pub sub, sts creds provider now built into profile based creds.

v0.6.4

added raw mqtt (without iot specific builders) sample. Updated to lat…

Added OnMessage support for receiving publish messages in mqtt that come on a topic that wasn't subscribed to explicitly

On any publish support (#69)

* Added OnMessage support for unsolicted messages.

* Implementation of on_any publish handler.

Update readme, fix windows builds where cmake_build_type isn't set.

v0.6.2

Fixed default cmake build without a specified CMAKE_BUILD_TYPE. (#68)