* Implemented install-from-registry command which installs all of the pr...

* Implemented install-from-registry command which installs all of the programs listed in installed-programs.json file. #23

first part of #61

BTW: if the `installed-programs.json`   is not perfect: e.g.  {"firefox": "2014-02-12-12:59"} which misses it's dependency it will still install firefox and build the required dependency

this might be nice if one wants to simple install a list of programs but does not want to define all dependencies one could do

JUST DID THE TEST
* $ sudo service docker stop
* $ sudo rm -rf /var/lib/docker
* $ sudo service docker start
* create: installed-programs.json
```
{
"firefox": "",  
"vim": ""
}
```
* $ subuser install-from-registry --from-cache

```
workerm@notebook:~$ subuser install-from-registry --from-cache

=== Installing <firefox> from installed-programs.json registry....

Installing libx11
Uploading context  2.56 kB
Uploading context 
Step 0 : FROM ubuntu

```

<b>all should be installed :+1: </b>

Final `installed-programs.json` will be overwritten and corrected

```
{"libx11": "2014-02-12-12:59", "firefox": "2014-02-12-12:59", "vim": "2014-02-12-12:59"}
```

```
workerm@notebook:~$ subuser list installed
libx11
firefox
vim
workerm@notebook:~$ 
```