tinyxml2 (1.0.11, latest commit at current) is now bundled in libvpvl2
removed tinyxml2 task and fixed compile error at release build
cmake 2.8.9 is now required, build option should be minimum as possible
renamed RENDERCONTEXT to APPLICATIONCONTEXT, fixed minimal build
call BaseApplication::(initialize|terminate) should be in main
rewrote SFML2 sample application
added Allegro5 based sample application
added VPVL2_ENABLE_LAZY_LINK option
implemented setting display option, fixed a crash bug after exitting