Changes since 1.5

Requires:
  - XML::LibXML 1.54

New features:
  - local (temporary) variables
  - subroutine may take parameters
  - forward defs (with no body) allow recursion
  - call strongly checks argument types
  - new location keywords: append, prepend
  - new location semantics (mostly clean-up)
  - perl-code result substitution in expressions using ${{{ ... }}}
  - string xpath result substitution in expressions using ${( ... )}
  - new Perl functions: literal, xml_list and count
  - new switch-to-new-documents flag (allows to disable selecting
  - simplified and more general open/save commands
  - support document level node insertion
  - improved error reporting from XSH grammar parser
  - docbook loading support
  - pipeline redirection may follow statements
  - grammar optimizations (some more speed-up achieved)

Other changes:
  - XSH now starts with validation 0
  - new xsh option -v allows starting with validation on
  - obsolete xsh -c flag removed
  - documentation enhancements

Bug fixes:
  - indentation fixes
  - fixed ReadLine::Gnu completion support
  - ~/.xsh_history works for Term::ReadLine::Gnu now
  - fixed doubled history entries
  - double/single quoting fixed in expressions
  - experimental support for entity reference insertion
  - fixed error catching
  - fixed and improved Ctrl+C handling
  - some more bug-fixes
