Add new tf.exe search locations.

Review Request #7107 — Created March 23, 2015 and submitted — Latest diff uploaded

Information

RBTools
release-0.7.x
ef28e92...

Reviewers

Visual Studio 2013 Update 4 has replaced tf.cmd with tf.exe. In order to
correctly detect TFS repositories, we need to now search for those locations.
I've added the generic tf.exe and the VS2013-specific path to our list of
search locations.

Updated my VM to use VS 2013 Update 4. Installed this and noticed that
rbt post could once again detect TFS work folders.