Initial commit, most of the files come directly from gtatools/libgtaformats or gtatools/libgta, SVN rev255, with some custom changes. The whole libgtaformats/util directory was moved here, and the ResourceCache class from libgta

Notable changes from the gtatools rev255 version include:
	- C++11 is now REQUIRED to build this library
	- The File classes were rewritten and extended (although much of the old code was reused) to be a little more robust. This had to be done because the old File system depended on the IMG classes from libgtaformats (IMG reading support through File APIs), and of course libnxcommon shouldn't depend on anything from gtatools.
		- ArchiveHandler API is now used to extend the basic File functionality. This is mainly used in libgtaformats to keep the IMG handling functionality working
		- FilePath class was extended to be aware of different syntaxes (Unix/Windows)
		- The FileIterator system was replaced by the FileChildList, which provides a new, STL-compatible iterator interface, so that File::getChildren() can be used in a range-based for-loop in C++11
		- Lots of other changes here and there
	- Some new functions in strutil.h/strutil.cpp
	- The directory structure was changed. It should be a little bit tidier now
	- nxcommon-test was added, which has some basic unit tests (for the File* classes right now)
	- All kinds of small changes
Some small changes to the build system, config.cmake.h, and some other details
- New AbstractSharedBuffer system, providing a base class for all kinds of copy-on-write data blocks, with currently the following subclasses:
	- CString is now based on AbstractSharedBuffer, for 8-bit ASCII-based encodings. NOTE: CString::get() does not return NULL for Null-CStrings anymore. Use CString::isNull() instead!
	- UString for UTF-16 encoded Unicode strings, handled through ICU
	- ByteArray for general-purpose, non-null-terminated binary data
- Use of ICU for Unicode support
- New, basic SQL module, with support for SQLite and MySQL (optional modules)
- Moved Lua scripting system from gtatools/libgta to libnxcommon
- Added PostgreSQL driver to SQL subsystem
- Added a few support routines for working with Qt4/Qt5 and Bullet (mostly conversion stuff)
- Hell knows what else I've changed...
Just some fixed to make it work on MinGW32
- Some bigger changes to the build system. It is now Config-file based for libnxcommon.
- Tidied up the code a bit, making nasty GCC warnings go away