Git path now should be passed as git option.
Emakefile doesn't require deps key.

Emakefile now doesn't require deps key. Some refcatoring provided.
Added ability to use dependency headers only.

Using dependency headers only means that dependency will not be built.
To make this possible the option {use, include} should be supplied with
the dependency.
Already compiled modules are now not compiled.

Recompilation also occurs if related header(s) was changed as well.