Fix #118

NEWS:
* Switching endianness mid-byte no longer potentially re-reads bytes.
* bit_offset now consistently refers to the number of bits already
  read.
* HParsedTokens now have a bit_length field; this is a size_t.  This
  may be removed for memory reasons.

The bit writer has not yet been updated to match; the result of
switching bit writer endianness in the middle of a byte remains
undefined.

src/SConscript

@@ -69,7 +69,8 @@ ctests = ['t_benchmark.c',
           't_bitwriter.c',
           't_parser.c',
           't_grammar.c',
-          't_misc.c']
+          't_misc.c',
+	  't_regression.c']
 
 libhammer_shared = env.SharedLibrary('hammer', parsers + backends + misc_hammer_parts)
 libhammer_static = env.StaticLibrary('hammer', parsers + backends + misc_hammer_parts)