corrected xpath axes fix from rev 167

Fixed xpath search when getting attribute value

ragel 6.1 fixes for hpricot_scan.java.rl; update jruby object access

Applied the updates to the ragel code for 6.1 to hpricot_scan.java.rl.

Updated decrated method used to access IRubyObject object:

new IRubyObject[]{runtime.newSymbol("buffer_size")}

becomes:

runtime.getCurrentContext(),new IRubyObject[]{runtime.newSymbol("buffer_size")}

The include statements in the main ragel code didn't
work with paths starting with ext/ so I made them
into relative path references which did work.

Updates to the Rakefile to support easy
compilation of the C ragel source code
using different ragel compilation strategies.
This is the default setting:

DEFAULT_RAGEL_C_CODE_GENERATION = "really_fast goto_driven"

which is -G2

The result is no test failures in C and only
one in Java: test_latin1_entities.

* Rakefile: use Ragel 6.1 or greater from now on.

* lib/hpricot/elements.rb: a more liberal xpath attr parsing from ticket #115. thanks, wrs!

* ext/hpricot_scan/hpricot_scan.rl: using RSTRING_PTR and RSTRING_LEN to support Ruby 1.9, thanks manveru!