User Request: Clean up the default keywords.txt

Assure that all c++ keywords are present and that nothing unrelated to the c++/arduino core is to be found in the default file.

An additional feature could be to only load the keywords.txt to the user libraries that are #included into the sketch.

If there are specific things missing / extra, you may want to open a Google Code issue for them: Google Code Archive - Long-term storage for Google Code Project Hosting.. Some C++ keywords may not be added (i.e. if they're not things we want to cover in the Arduino reference).

Not to cover it in the documentation is one thing, but to give the impression that the keyword does not exist under Arduino is an entirely different thing.

struct enum union sizeof

Some examples.

Again, the best way to ensure this doesn't get lost is to open an issue for it.