Fix of Issue 11338

- URIerror renamed to URIexception
- URIexception class inherits from Exception
Fix Issue 11338
- Now call the onOutOfMemoryError() function when alloca returns NULL
- Fixed the URIexception name to URIException
- Added a string constructor for the URIException class
- Added more informative messages to some of the errors
Fixing Issue 11338 - Additional

- Now all thrown URIException have human readable text
- throw new OutOfMemoryError("Alloca Failure"); // Make code look more consistant
Fixing exception casing to line style, added better exception message for missing hexadecimals
Merge pull request #1659 from DannyArends/issue_11338

Fix Issue 11338 - std.uri URIerror should be an Exception