Change injector to task_vaccine

[rodionovd]

task_vaccine is a modern successor of rd_inject_library() with lots of improvements (e.g. it supports injection into i386 targets — #4).

TODO list:

• [ ] add a demo i386 target
• [ ] add a test case for i386 target
• [ ] replace rd_inject_library with task_vaccine
• [ ] update tests (make them fully automatic)
• [ ] set up Travis CI to build and test the project

(so actually moving to task_vaccine means a brand new 0.2 release).