The OpenGEX importer defined a few global std::string constants, only to convert them back to C strings on use. This commit defines them as C strings from the beginning.
strncmp() was used to compare these strings to other strings, but the length limit was set to string length, which made it equivalent to strcmp(), just slower. Fixed that as well.
std::string s(""); s = ""; calls the copy constructor, which in turn calls strlen(), … assigning a default-constructed string generates fewer instructions and is therefore preferred.
With C++11 uniform initialization, you’d simply write s = { } instead.
