[Patch] Externalize messages

[Kev Jackson <ke...@it.fts-vn.com>]

This patch extracts (some) of the usage messages from o.a.t.a.Main into 
a resource bundle for easier editing/i18n.

- externalized strings (Main)
- name-hiding (Main)
- use StringUtils.LINE_SEP instead of locally getting line.seperator 
property (Main + other classes), I didn't get chance to replace all of these

Included a base main_messages.properties file, but my 2nd language 
skills are very poor, so I decided against including a translated 
version.  I may get someone here (in work) to contribute a 
Vietnamese/Japanese bundle at a later date.

Kev