added i18n support for security PaletteFormComponent's
User Guide - Working with SLD improvements
User Guide SLD Ref - labeling sections edits
Merge pull request #122 from fgdrf/i18n-palette-headers

added i18n support for security PaletteFormComponent's (web-security)
GEOS-5602 REST GETs and authentication under 2.3
GEOS-5608 Make the exception translation filter configurable