fixes #172

Removed separate compilers
Resolves apps to build
Finds avail deps before pulling/building
Includes relx
Simplifies build commands

* fix overlong lines
* where appropriate use %% instead of %

We use namespaced_types option to choose between dict() and dict:dict() types.

Always-on recursive application of all rebar commands causes too many
issues. Recursive application is required for:
1. dealing with dependencies: get-deps, update-deps, and compile of deps
   right after get-deps or update-deps
2. projects with a riak-like apps/ project structure and dev process

The vast majority of projects are not structured like riak. Therefore,
moving forward it's best to (by default) restrict recursive behavior to
dealing with deps. This commit does that and also adds command line and
rebar.config options for controlling or configuring recursion. Also, we
introduce two meta commands: prepare-deps (equivalent to rebar -r
get-deps compile) and refresh-deps (equivalent to rebar -r update-deps
compile). riak-like projects can extend the list of recursive commands
(to include 'eunit' and 'compile') by adding
{recursive_cmds, [eunit, compile]} to rebar.config.

{port_specs, [{".*", "priv/foo.so", ["c_src/foo.c"], [{env, []}]}]}.

Currently the --config switch does not work because when loading
a new rebar config the global setting is ignored for all paths.
This patch provides a check when loading new rebar config to see
whether or not the current config path matches the `base_dir` set in
global conf, which produces the expected behaviour.