Syntax errors lead to crash

After updating to the latest Dyna and Haskell libraries, I've noticed that syntax errors still lead to the backend crash like in #71. This happens because returned error string now contains terminal color tags like `\x1b[0m` for nicer output - those tags must be removed before parsing. For the test simply enter ` 2 + 2. ` in Dyna.

dijkstra.rst changes are just right-aligning shorter number for a nicer look.

I promise to learn and use GIT feature-branches for my next pull request =)