Closes #470 - Adds fetch command to Repository explorer

Closes #354 - Adds line history explorer (wip)
Closes #456 - Adds repository status to the repository nodes

Updates dependencies

Replaces git content provider with git fs provider
Adds Buffer output support to git calls

Adds new ${changes} and ${changesShort} template tokens
Adds support for prefixes and suffixes around tokens
Fixes missing/mismatched token option issues

Renanes "Compare x with" commands

Fixes #405 - stops non-repo from showing up in explorer

Removes Uri monkey patch as it no longer will work
See 03432806c8
Stops encoding uris in .toString calls

Removes gitlens.advanced.git setting

Removes start logging from isTracked

Changes from out to dist
Adds size-plugin (commented out for now)
Adds image cache to improve bundle performance

Adds new webpack tree shaking plugin

Uses webpack for all of it