Update Typings Acquisition / Intellisense Wiki pages for NTVS 1.2 Beta

[mjbvz]

NTVS 1.2 beta makes major changes to the Intellisense options page: #981. We need to update the wiki to reflect these changes.

We should merge sections of https://github.com/Microsoft/nodejstools/wiki/ES6-IntelliSense-Preview-in-NTVS-1.1 with https://github.com/Microsoft/nodejstools/wiki/Automatic-Typings-Acquisition and also update any sections that are out of date.

We should also keep the existing documentation around and be careful not to break any existing links (possibly by updating aka links that have already been deployed pre NTVS 1.2) For the future, we may want to consider moving to using a regular GitHub repo for documentation instead of a wiki repo, as this allows versioning documentation more easily.

[mjbvz]

Updated this page to have both 1.1 and 1.2 info: https://github.com/Microsoft/nodejstools/wiki/IntelliSense-and-Editing

Also updated https://github.com/Microsoft/nodejstools/wiki/Automatic-Typings-Acquisition for 1.2 beta.