Monkey patching shell provisioner for windows

This commit adds monkey_patches to make shell provisioner to work
on windows.

Fix mkdir parameter
mkdir parameter did not work properly
Bump version to 1.0.3
Added win_friendly_path method to convert unix style paths to windows style paths
Updated gemfile and lock to point to vagrant 1.1.5, since later versions are incompatible
Use the builtin vagrant source_root path for finding the vagrant folder. This is more reliable, works with bundler, and reduces duplication.

Modified the shell provisioner to support inline scripts.
Updated readme for shell provisioner
Merge pull request #46 from WinRb/pr/45

Shell provisioner support