Convert plRegistryNode stuff to plString.
Fix issues pointed out in code review.
Fix memory leaks.
Add plString::Replace
Merge pull request #254 from zrax/plstring-replace

Add plString::Replace
Merge pull request #253 from zrax/plString

Fix a major plStringStream bug, and add an SSO-like optimization to it.
Fix format string here.
Some fixes to make it all compile.
Merge pull request #251 from dpogue/plresmgr-strings

Convert plRegistryNode stuff to plString.
Generate ComCtl manifests for the Win32 GUI executables
Merge pull request #256 from zrax/win-themes

Use Windows themes for the Win32 GUI executables
Add Truncate() method to plStringStream, which truncates the buffer without reallocating memory