Enhanced Pry history to be shared with IRB history.
Enhanced .pryrc to default to Sublime Text editor.
Enhanced Pry alias commands to be only defined if the Byebug debugger is present.
Cleaned up the .pryrc file and related options.

* Moved the "whereami" alias outside of the Byebug aliases.
* Removed duplicate Pry prompt code.
* Fixed issue where writing Pry history to the .irb_history file would cause an exeption.
Enhanced prompt to show dirty and unstrack file status for git branch.
Enhanced prompt to display Git stash state and upstream differences (if any).
Converted the gail alias to a function.
Enhanced shell prompt to only show current directory and not the full path.
Enhanced bash prompt to show git branch and committer email address with a blue background for current project.