Fix LP_TITLE_CLOSE on bash inside screen
Fix LP_TITLE_CLOSE on bash inside screen

As the TITLE_CLOSE sequence for screen contains a '\', and this char is
the escape char for PS1 in bash we have to escape it.
Cc: @pkkolos

Note: there are more places where % or \ should be more properly
escaped, but this is a huge work. This is a bit like XSS in HTML.
In angel-PS1 I solved the issue by design.

joshuarubin/dotfiles,dpilone/liquidprompt,joshuarubin/dotfiles,joshuarubin/dotfiles,laurentbardin/liquidprompt,dan-cleinmark/liquidprompt,dtschan/liquidprompt,joshuarubin/dotfiles,smadhueagle/liquidprompt,nojhan/liquidprompt,tsbarnes/liquidprompt,alexprengere/liquidprompt,jaesivsm/liquidprompt,milouse/liquidprompt,pkkolos/liquidprompt,BobHood/liquidprompt