Fix right aligned statusbar item redrawing

Fixes Github issue #97 https://github.com/irssi/irssi/issues/97

Fix proposed by ailin-nemui, built and tested on Debian Jessie using
0.8.15 source, tested by GeertHauwaerts as well.
Applied grammar and styling corrections

Applied grammar and styling corrections.
Updated ALIAS help

Updated ALIAS help.
Merge pull request #109 from cpbills/master

Fix right aligned statusbar item redrawing