win-capture: Add obfuscation functions

This adds obfuscation functions primarily for use with GetProcAddress.
This takes an obfuscated string and uses a simple integer key to
de-obfuscate it to the intended function name string, which is then
loaded dynamically using GetProcAddress.

This is typically only used with functions such as OpenProcess,
SetWindowsHookEx, and the like, which can often be misinterpreted the
wrong way by security programs if those strings are found within the
strings segment of a scanned executable.