Add support for minimum OTP versions.

Since you can't really do math with regexps and it's a pain to
repeatedly update the config for each new version or erlang, I wanted
to add support for minium OTP versions.  This is a fix for
https://github.com/basho/riaknostic/issues/38
Add skip_deps=AppListSeparatedByCommas feature
Add support for non-Erlang/OTP (raw) dependencies

Introduce a new 'raw' option for dependency specs in rebar.config file.
For example:

{deps,
    {dependency_name, "1.0.*",
	 {git, "<...>", {branch, "master"}},
	 [raw]
    }
]}.

When this option is specified, rebar does not require the dependency to
have a standard Erlang/OTP layout which assumes presence of either
"src/dependency_name.app.src" or "ebin/dependency_name.app" files.

'raw' dependencies can still contain 'rebar.config' and even can have
the proper OTP directory layout, but they won't be compiled.

Only a subset of rebar commands will be executed on the 'raw'
subdirectories:

	get-deps, update-deps, check-deps, list-deps and delete-deps.
Add hostname variable to reltool overlay templates
Fix return value of rebar:overlay/2

When 'rebar overlay' is run rebar_core got a wrong result
{Config, ok} from rebar_reltool instead of {ok, Config}.
Merge pull request #326 from saleyn/hostname_var

Add hostname variable to reltool overlay templates
Merge pull request #325 from saleyn/reltool

Fix return value of rebar_overlay
Adding Serge Aleynikov to THANKS
Merge pull request #217 from alavrik/raw_deps_new

Add support for non-Erlang/OTP (raw) dependencies
Specify multiple locations of DTL template files

Added a backward compartible feature to specify `erlydtl_opts' options
for the DTL template compiler to allow inclusion of templates in different
directories with different compilation settings for each. E.g.:

    {erlydtl_opts, [
          [{doc_root, "src/view"}, {module_ext, "_dtl_vw"}]
        , [{doc_root, "src"},      {module_ext, ""}, {recursive, false}]

        , {out_dir,   "ebin"}
        , {compiler_options, [verbose, debug_info]}
    ]}.

The definition above is identical to this (the last two options
are duplicated in each list):

    {erlydtl_opts, [
          [{doc_root,   "src/view"}
          ,{module_ext, "_dtl_vw"}
          ,{out_dir,    "ebin"}
          ,{compiler_options, [verbose, debug_info]}]

        , [{doc_root,   "src"}
          ,{module_ext, ""}
          ,{out_dir,    "ebin"}
          ,{compiler_options, [verbose, debug_info]}
          ,{recursive, false}]
    ]}.

In this case "src/view" and "src" directories containing template files
will be compiled.  A new `recursive' option tells rebar_erlydtl_compiler
to search files recursively from a given doc_root.  In the example above
the "src" directory won't be scanned recursively, and the target template
name for target beam modules won't have "_dtl_vw" suffix.
Made more readable printout of the erlydtl compiler message

The printed message is made more terse.

Example before applying patch:

    ERROR: Compiling template src/view/test.dtl failed:
      {error,{"src/view/test.dtl",
              [{{4,7},
                erlydtl_parser,
                ["syntax error before: ",["\"\\\"HELLO_WORLD\\\"\""]]}]}}

Example after applying patch:

    ERROR: Compiling template "src/cmp_html_error_template.dtl" failed:
        (line:3, col:12): ["syntax error before: ",["trans"]]
Fix rebar_base_compiler:format_errors/3 for errors in include files

Handle the case where the error didn't occur in the file being
compiled.  That is, if there is an error on line 9 of bar.hrl,
instead of:

/path/to/foo.erl:9: type foo() already defined

print:

/path/to/bar.hrl:9: type foo() already defined
Add Magnus Henoch to THANKS
Fix erlydtl dependency check

When a DTL template includes other template files, those files don't need
to be compiled separately, and therefore can be given an extension different
from `source_ext` (such as `.dtli`) to avoid being compiled.  This fix
allows rebar to find included dependencies with names `*.dtl*` rather
than `*.dtl` and properly determine if a template file needs to be recompiled.
Revert arch string changes
Merge pull request #1 from tuncer/ta-old-arch_string

Revert arch string changes
Merge pull request #243 from evanmcc/pevm_min_otp_version

Add support for minimum OTP versions
Merge remote-tracking branch 'basho/master'
Various updates for README to reflect new home for rebar
Updating .travis.yml for new primary repo