Fix clang compile errors
Fix all compile errors emitted when compiling with Clang.
Most fixes fall into the following categories
- Using
QString::latin()
to convert QString to ascii C-String so it can be printed using C-style functions - Resolving implicit const to mutable conversions, either by doing a copy, making the source const or using const_cast with a comment
- Invalid UTF-8 encoding
- Adding space between Macros and C strings
- Removing
register
keyword
There's also some minor non-required fixes such as correcting some header guard mismatches.