Bumped version, updated dependencies

• Underlying multibundle has breakingg change, so bumping package's version.
• Updated readme and tests

multibundle@1.2.0

Updated multibundle to 1.2.0

Missing devDependency

• Added (missing) grunt-eslint as development dependency.
• Added "stable" version of node to the travis config.

Async Mapping

• Added support for async mapping

Armored Mapper

Grunt is messing up with objects passed in options, protecting mapper instance by wrapping into a function.

Final Destination

• Auto creates destination folder if it doesn't exist

Non-Shared Paranoid

• Fixed handling non-shared modules (extra defensive checks).

Exclude All The Things!

• Properly exclude shared modules with shared paths

Parallel

Switched to use multibundle internally.

• Allows faster (parallel) processing and more functionality (multiple shared bundles).