Adding support for Unicode input files to most text file loaders (BVH and MD5 missing for now).

IrrXML receives memmapped UTF-8 input data now, it's own (faulty) conversion is not used anymore.
aiString's are explicitly UTF-8 now.
Slight refactorings and improvements.
Adding UTF-8/UTF-16 text files for ASE,obj,collada,ac3d. These contain various japanese/chinese character sequences.
Changing assimp_view's node view to display UTF-8 multibyte sequences correctly.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@469 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/ACLoader.cpp

@@ -726,19 +726,18 @@ void AC3DImporter::InternReadFile( const std::string& pFile,
 	if( file.get() == NULL)
 		throw new ImportErrorException( "Failed to open AC3D file " + pFile + ".");
 
-	const unsigned int fileSize = (unsigned int)file->FileSize();
-
 	// allocate storage and copy the contents of the file to a memory buffer
-	std::vector<char> mBuffer2(fileSize+1);
-	file->Read(&mBuffer2[0], 1, fileSize);
-	mBuffer2[fileSize] = '\0';
+	std::vector<char> mBuffer2;
+	TextFileToBuffer(file.get(),mBuffer2);
+
 	buffer = &mBuffer2[0];
 	mNumMeshes = 0;
 
 	lights = polys = worlds = groups = 0;
 
-	if (::strncmp(buffer,"AC3D",4))
+	if (::strncmp(buffer,"AC3D",4)) {
 		throw new ImportErrorException("AC3D: No valid AC3D file, magic sequence not found");
+	}
 
 	// print the file format version to the console
 	unsigned int version = HexDigitToDecimal( buffer[4] );