restore window title

The msys shell used to be able to display the window title as "MINGW32:<pwd>", which was very useful when multiple shells were open. This behaviour was lost due a series of commits, namely
 - 4e4e3f3fefab0ead3aa0b4822675355d40303b10
 - 759a59f67bfcb7cf1fb11f289d04398eb78de908
 - 0433db08af3db8454dd90cb416060dae2fe64716

This pull request/branch was constructed by first basing on 4e4e3f3fefab0ead3aa0b4822675355d40303b10 and fixing the annotations. 759a59f67bfcb7cf1fb11f289d04398eb78de908 and 0433db08af3db8454dd90cb416060dae2fe64716 were then reverted via merges. Merges were used to ensure this information was captured in the git history, as well as ensure conflict-free merging into upstream.