Translator – Some Minor Improvements

The done stack pop error token function was used create an error token from the item on top of the done stack.  An item on the done stack could consist of an entire expression so in addition to a token, it contained the first and last tokens of the expression, which would be null if the item only contained a single token.

There is no need to create an error token since exceptions are now thrown for errors, which do not contain tokens.  All callers to this function only used the error token to create a token error (status with the column and length from the error token).  This function was modified to return a token error and was more appropriately renamed to the done stack top token error function.  There is also no need to pop the done item from the stack since when an error is thrown, the translator instance goes out of scope and all members are deleted including the done stack.

Several other minor changes were also made including removing the token set through function since it was no longer used, replacing the uses of the Qt forever macros with a plain empty for (;;), renaming the expected error status function (had "Error" abbreviated as "Err"), adding the C++ noexcept keyword to translator functions that do not through an exception, and updating a few comments missed for changes made earlier.

[branch misc-cpp-stl commit 625195f18d]