Sync .virtualenvs from VM to home/.virtualenvs [#25]

Update notice: existing virtualenvs will not work, need to recreate virtualenvs
$ vagrant reload to get the changes
Sync .virtualenvs from VM to home/.virtualenvs: windows symlink [#25]

To make virtualenv work, you must run git bash and virtualbox as administrator on windows.

How to update:
+ $ git fetch origin
+ $ git merge origin/master
+ restart windows
+ from now on, *always* run virtualbox and git bash as *administrator*
+ $ vagrant reload
And it's all, you can use vagrant as normal.
Sync .virtualenvs from VM to home/.virtualenvs: update README [#25]
Merge remote-tracking branch 'hoatle/enhance_25_sync_virtualenvs_vm_to_host_home_dir' into develop
Revert the changes of #8 that cause chef reports error when '$ vagrant halt' and then '$ vagrant up' [#23]
chef reports error when '$ vagrant halt' and then '$ vagrant up': New better way of ssh config [#23]

5. **How to use ssh keys on the virtual machine**?

``teracy-dev/home/.ssh`` on the host machine and ``~/.ssh`` on the virtual machine are in sync. You
could copy your existing ssh keys into one location and it will be available in the other location.

For example, to use existing ssh keys, type the following commands on the host machine terminal
window:
::
    $ cd teracy-dev
    $ cp ~/.ssh/id_rsa* home/.ssh

Or to create new ssh keys on the virtual machine, just create it and these keys will be copied into
``teracy-dev/home/.ssh``.
Merge remote-tracking branch 'hoatle/hot-fix_23_error_when_vagrant_halt_then_up' into develop
add allowed hosts of github, bitbucket to virtual machine [#3]

+ Update README for vm.ssh.forward_agent usage
+ add allowed hosts
Merge remote-tracking branch 'hoatle/enhance_3_add_github_butbucket_to_allowed_hosts_vm' into develop
Fix big problem: ssh does not work on Windows host machine [#23]; this fixes windows password prompt [#30]
Merge remote-tracking branch 'hoatle/hot-fix_23_error_when_vagrant_halt_then_up' into develop