Moved Timer into util subdir.
Moved tinythread into util subdir.
Moved OTAssert into util subdir.
Moved StringUtils into util subdir.
Moved stacktrace into util subdir.
Moved OTWindowsRegistryTool into util subdir.
Moved win32_utf8conv into util subdir.
Moved OTCommon into util subdir.
Removed thread_local define because it was unused.
Include fixes.
Removed OTglobal.h
Minor cleanup.
Cleaned up includes of OTCommon.
Merge pull request #69 from murrekatt/develop

Moved util files into own subdir in core