Adds files: error 1 to 5 and variation 1 to 4

tests for error1: not well formed xml

tests for error2: not well formed xml attribute without colon

tests for error2: not well formed xml, typo

tests for error4: wrong xml version

tests for error5: extra content at the end of the doc

tests libxml_dtd_load

tests libxml_dtd_valid

tests for libdtd_noerror

tests for LIBXML_DTDATTR, LIBXML_NOCDATA, LIBXML_NOENT and LIBXML_NOBLANKS

the basic behavior

fix comments
Merge branch 'master' of https://github.com/dejalatele/php-src