Add nemo-terminal package

This is a port and fork of the [nautilus-terminal package](http://projects.flogisoft.com/nautilus-terminal/).

I have added a number of integration improvements on the base-package - rather then a standalone config file it reads settings from a GSettings profile under `org.nemo.extensions.nemo-terminal`, correctly follows the Nemo window into GVFS shares (using the GFile interface to convert URIs) and adds support for "paste filenames" functionality.

The default hot-key to open and close it is F4, the default visibility and other settings can be adjusted under the relevant keys in dconf-editor. My idea for a UI for configuring these settings in nemo is currently open under linuxmint/nemo#428.

nemo-terminal on Nemo 2.0.2:
![nemo-terminal](http://i.imgur.com/xvewUft.png)