Added copyright, various description notes.
Added CMS_EXTERNAL_LINK, and improve various link interfaces.
Structured the model library with sub folder: user, link and content.
updated readme.
Renamed model-safe.ecf as cms_model-safe.ecf since it is very specific to the cms.
Fixed compilation issue due to recent use of STRING_TABLE.
Merge pull request #10 from jocelyn/copyright_20141113

Added copyright, note, and minor improvements.