Escaped HEX codes break the parser

[brainlid]

Elixir 1.5.2
sweet_xml 0.6.5

The following XML file will break the parser

SweetXml.parse("<test>Some Text&#x1A;</test>")

The error is:

** (exit) {:fatal, {{:error, {:wfc_Legal_Character, 26}}, {:file, :file_name_unknown}, {:line, 1}, {:col, 22}}}
    (xmerl) xmerl_scan.erl:4117: :xmerl_scan.fatal/2
    (xmerl) xmerl_scan.erl:2908: :xmerl_scan.scan_char_ref_hex/3
    (xmerl) xmerl_scan.erl:2572: :xmerl_scan.scan_content/11
    (xmerl) xmerl_scan.erl:2133: :xmerl_scan.scan_element/12
    (xmerl) xmerl_scan.erl:575: :xmerl_scan.scan_document/2
    (xmerl) xmerl_scan.erl:291: :xmerl_scan.string/2
    (sweet_xml) lib/sweet_xml.ex:233: SweetXml.parse/2
[error] 3429- fatal: {:error, {:wfc_Legal_Character, 26}}

It is incorrectly unescaping the escaped HEX value for ASCII 26, which is an invalid XML character.

I have worked around the issue for my own needs.