Can't run the test program

```
➜  branan-gltext  g++ test.cpp -o test -lGL -lglut -lGLU -lgltext `pkg-config --cflags freetype2` `pkg-config --libs freetype2`
➜  branan-gltext  ./test 
terminate called after throwing an instance of 'gltext::FtException'
  what():  Freetype error occured
[1]    1035 abort      ./test
➜  branan-gltext  
```
