Bug 1072702 - The addon-sdk 'activate' script updates a working shell's PS1, but it's processing is insufficient for more sophisticated shell PS1's whose first char is a newline

Added PS1nlChk(), doPS1nl() functions to account for original PS1's, whose first 2 chars represent a newline. PS1 gets adjusted accordingly; so that the new PS1 version too, begins with a newline.