Visual Studio 2010 sln updates
Handle parsing merge commit messages with multiple TFS changeset ids

The original code would null out currentCommit after parsing the FIRST changeset id in the
log message, and associate the null commit hash with any additional changeset ids in the message
for the same commit. This eventually leads to a null reference error when executing git commands
that require the hash.

The new code ignores all of the changeset ids in the commit message except for the last one, which
is the only one that matters.
Revert "Visual Studio 2010 sln updates"

This reverts commit c4a3511f49373682aa8004acb13e24f47aae6dc8.
Cleaning up logic around currentCommit variable
Merge pull request #308 from dougwebb/master

Only use the last git-tfs-id line from a commit message (e.g. a merge commit message).