* win32_slim.h: includes the minimal version of windows.h
modified:
* cthread: added lock_t c++ class
* os: added getUserName()
* socket: modified socket_len_t to sk_len_t to better follow naming convetions in file
* str: added operator std::string() to str_t
* coroutines
* string
modified:
* http: fixed a couple of bugs
* strutils: renamed to os, it is now a header for some generic platform-indipendent code
* tracelog: added option to not print newline at the end of a message + bug fixes