Fixed typos in doc comments. Added doc comment on how to override the NullText and NotAvailableText values.
Fixed typos in doc comments. Added doc comment on how to override the NullText and NotAvailableText values.

git-svn-id: 223c0ba935819ffdcafdc68147dc609b4e469b1e@382402 13f79535-47bb-0310-9956-ffa450edef68

harold4/log4net,modulexcite/log4net,amtkmrsmn/log4net,harold4/log4net,drunkirishcoder/monotouch-log4net,harold4/log4net,StevenJiang2015/log4net,amtkmrsmn/log4net,Dagwaging/log4net,modulexcite/log4net,Dagwaging/log4net,amtkmrsmn/log4net,StevenJiang2015/log4net,modulexcite/log4net,drunkirishcoder/monotouch-log4net,Dagwaging/log4net,drunkirishcoder/monotouch-log4net,StevenJiang2015/log4net,drunkirishcoder/monotouch-log4net