Some more minor improvements

[tannergooding]

• Adds a config switch to ignore any default remappings added.
• Resolves the full path of -o so that -o file.cs works (it was creating a directory with that name currently)
• Adds a --traverse option so that you can -f header.cs and then generate bindings for a nested include
  • This is useful when you need to generate bindings for a header file which isn't "standalone"
• Fixes CXUnsavedFile and CXTUResourceUsageEntry to use uint on Windows and UIntPtr on Unix for their unsigned long usages
  • Going to log an issue tracking a general purpose solution for this, so it isn't manual

[tannergooding]

Also pushed up a commit which simplifies how the opcode for a binary/unary operator is computed.

The logic in BinaryOperator specifically wasn't accounting for the fact that LHS could itself be a non-parenthesized binary expression.

Now, it just grabs the first opcode after the LHS expression, which should always be the opcode.