Added proper symlink support to tar/untar

Symlinks where being treated as regular files and copies
of the files where stored instead of links for files and
broken regular files with no content instead of folders.
Now Lstat is being used to read the file details, which
does not follow symlinks but instead returns the link
details, which allows to add them as symlinks to the tar.
Make tilde expansion work on Windows
fixed tests on Windows
Changed chmod call for windows compatibility
Fixed outdated import
Merge pull request #34 from bogdanteleaga/chmod-windows

Changed chmod call for windows compatibility
Merge pull request #18 from perrito666/add_symlinks_support

Added proper symlink support to tar/untar
Add a set implementation for the names.Tag type
set/tags: update tests per review comments
utils/set: make interfaces private
set/tags: more test updates
utils/set: clean up Tags tests
Added cross platform Uptime() function
Merge pull request #35 from wwitzel3/ww3-tag-set

Add a set implementation for the names.Tag type
Merge update to use gopkg.in/check.v1
go fmt fixup
Merge pull request #27 from gabriel-samfira/testing

Make tilde expansion work on Windows
Merge pull request #39 from gabriel-samfira/uptime

Added cross platform Uptime() function