Merge branch 'develop'
SCM: Git clone performance

Via:
- http://stackoverflow.com/questions/1778088/how-to-clone-a-single-branch-in-git
- http://stackoverflow.com/questions/6941889/is-git-clone-depth-1-shallow-clone-more-useful-than-it-makes-out
- http://git-scm.com/docs/git-clone
Merge pull request #125 from xboston/patch-1

SCM: Git clone performance
Add task for force updating a working copy

Downloads the latest from remote without trying to merge or rebase
anything. Resets the master branch to what you just fetched. Changes all
the files in your working tree to match the files in origin/master, so
if you have any local changes, they will be lost.
exclude from file added.
rebased by upstream
small fixes @ rsync and targz tasks
added relative linking @ Link shared files task
relative linking @ Link shared files task.  Added exclusion rules to symlinks creation.
small fixes @ link shared files task. wrong constant value
changes @ deploy command. added rollback exception functionality.
added config reload @ after rollback exception
Merge pull request #146 from samuel4x4/develop

Add task for force updating a working copy
Merge pull request #148 from gudron/exclude_from_file

Rsync , TarGz exclude from file
Tweak excludes files.
Merge pull request #149 from gudron/relative_linking

Relative linking @ shared file task.
Merge pull request #150 from gudron/rollback_exception

Rollback exception
Fixes #131
Related to #130
Fixes #121
Merge branch 'master' into develop