thousands separators in numeric values and validating fields.

Changes add commas (or thousand separators) to the numeric fields.  The code is designed to pull the thousand separator character from the user's locale setting.  Rather than comma this could be another comma appropriate for the locale or a character custom set by the user.  

This idea has been proposed by myself and by others 
https://bitcointalk.org/index.php?topic=286429.msg3064616#msg3064616
https://bitcointalk.org/index.php?topic=221301.msg2332622#msg2332622

The most common argument against the idea has been that we should use something other than commas for thousand separators.  This is something a user can set in her locale settings.