* Added line in `UndoLastCommitAction` to get the previous commit msg and store in `IStorageService`.
* Added `UpdateCommitInputPrevCommitMsg` that checks for that key in storage, and use it then remove it if it exists.
  * This does not suffer from the previous bug that blanked out the commit msg if you unstage a file.
  * Added a clause if the undo last commit fails to remove the key from storage. This way, it doesn't stay in there and get used later (I was scratching my head when it showed up later).

* Removed all previous commit message code.
* Changed `getCommitInfo` call to return a string that is the template contents.
  * Removed from `IModel`, `IRawStatus`
* Still has issue of locating `~/some/path/with/tilde` in it.
  * path.resolve resolves to the repo's `.build` path and not the user folder.
  * I'm testing this on Windows, and I don't know the behavior on Linux.

* Refactored `status` to `model` in lambda callback. This reflects the actual item being returned.

* Seems to be working with limited testing.
* I am using `IStorageService` with no explicit scope, and I am unsure of the implications of this.
* There might should be an option for this functionality.

* Cleaned up and corrected changeView calling code to avoid initial git commit msg stuff.
* Refactored `lastCommitMsg` to `prevCommitMsg` in pipeline.

* Added `getCommitInfo` to git `IModel`.
  * Added commitInfo to Model implementation class.
* Changed `IRawGitService.getCommitInfo` to return `IRawStatus` instead of `ICommitInfo` directly.
* Changed `IGitService.getCommitInfo` to return `IModel`.
  * This was required because it expects a status when performing a git operation from the client (not really documented nor obvious).

* Added `Repository.getLog(ILogOptions)` for getting the previous commit msg, but allowing extensibility.
  * Added `ILogOptions` with single `prevCount` for extensibility of other use cases when executing `git log -1` (which gets the previous commit msg).

InProgress:

* Implementing getCommitInfo to parse possible template file, as well as parse the previous log message.

* I'm going ahead and commiting changes for possibility of others seeing this code. I will rely on later being able to correctly rebase changes.
* Added `getCommitInfo` to the git command chain: `IRawGitService`, `GitService`, `GitChannel`, `ChangesView`.
* Is erroring in a side-effect that I am having problems debugging, as the contributing guidance doesn't explain debugging the node process side (explicitly anyway).

fixes #2100

fixes #1544

# Conflicts:
#	src/vs/languages/html/common/htmlTags.ts