0.6.8 - Hammering the install and packaging process

Example logfile: https://gist.github.com/shiftkey/aa16df76e6c58484c081/raw/70ec03b35e0460cea5f1d893e3a78e2af811948b/WpfApplication1.txt

`New-Release` output:

![screen shot 2013-09-01 at 9 00 19 pm](https://f.cloud.github.com/assets/359239/1063859/cdf2ae12-12f5-11e3-9fc1-9159d14fcb64.png)

A bunch of bugfixes in here:

 - Installer should only run for the latest release, not every release it finds
 - The output from `CreateReleasePackage` now lists three files - these are displayed correctly
    - the full package
    - the base package for the delta package (currently wrong, should be previous release instead of latest release)
    - the delta package
 - tabs tidied up to spaces now
 - `New-Release` now work even when you're in a folder with spaces - resolves #68 

TODO:

 - [x] tracing around `InstallManager` and `UpdateManager` to highlight bugs raised by users [here](https://github.com/github/Shimmer/issues/44)