(1) Trailing/leading spaces are removed from 'name's/'blurb's
(2) Duplicate 'blurb's are replaced with NULL
(3) Empty ("") 'blurb's are replaced with NULL
(4) BASE_NONE, NULL, 0x0 are used for 'display', 'strings' and 'bitmask' fields
for FT_NONE, FT_BYTES, FT_IPv4, FT_IPv6, FT_ABSOLUTE_TIME, FT_RELATIVE_TIME,
FT_PROTOCOL, FT_STRING and FT_STRINGZ field types
(5) Only allow non-zero value for 'display' if 'bitmask' is non-zero
svn path=/trunk/; revision=28770
When offset parameter is 0 replace tvb_bytes_exist() with the faster tvb_length().
On the other hand
if (tvb_bytes_exist(tvb, 0, 20)
is more readable than
if (tvb_length(tvb) >= 20
so only do it in heuristic function
svn path=/trunk/; revision=23412
