XTrie implementation

Author: Francisco Claude <fclaude@cs.uwaterloo.ca>

This trie implementation considers only the tree generated by the xml 
(tags and attributes), the text is not represented and the index does
not replace the original xml file. The implementation requires 
libxml++2.6, for installing it in ubuntu execute:

  sudo apt-get install libxml++2.6-dev libxml++2.6-2 libxml++2.6-doc

This code was writen while visiting Sebastian Maneth and Kim Nguyen 
in NICTA, Sydney, Australia. 

Example of use:

$ ./gen_xml -f 1 > test.xml
$ ./parser test.xml index
$ ./engine index
> help

  Valid commands: 
  - help: shows this message
  - //a/.../b: searches for path a/.../b
  - size: shows the index size
  - quit: finishes the program
  - exit: finishes the program

> //keyword

  (results: 69969 | time: 2.35764ms | index size: 5437Kb)

> size

  Index size: 5437.84Kb

> quit

$