Wrote the device and data access tutorial
Added the simulation for the tutorial
Changed start topology
Added tutorial to tutorial index list
Changed directory name to device_data_access cause this tutorial should cover both. Also made some typo fixes in steps.js
Deleted old directory
Fixed typos and other expression errors
New Icon
Fixed some typos. Added links to helppages for external networks. Removed the TODO in the link_emulation with the needed check.
Merge pull request #725 from swuest/device_access_tutorial

Device access tutorial
Merge pull request #728 from swuest/chat_link_tut_help_pages_add

Added Helppages and made some fixes to Chat and Link Emulation tutorial