Removed unused variables.
On branch rtf-variables-refactoring
modified:   xsl/xslrtf/inc/rtf_variables.xsl
Splitted the RTF prolog in separate sections for better maintainability.
On branch rtf-variables-refactoring
modified:   xsl/xslrtf/dita2rtfImpl.xsl
modified:   xsl/xslrtf/inc/rtf_variables.xsl
Corrected typo.
On branch rtf-variables-refactoring
modified:   xsl/xslrtf/inc/rtf_variables.xsl