Save 14 bytes for generated langs.png

Strip ancillary PNG chunks on TruePNG optimization pass.

Before this change, only one such chunk, 'bKGD' (default background),
was present in the processed file. We won't miss it, as we don't have
transparency anyway.
Merge pull request #45 from tvasenin/master

Save 14 bytes for generated langs.png
* upgraded my laptop to Ubuntu 14.10.
* add the dependency to iconx.

Fixes #48.
* make coffeescript portable.

See #47.
* number each banner of Makefile.
* rename: "CommonLisp" -> "Common Lisp"
* remove "tcc" from the apt-get command.
* use "ghc" instead of "runghc".

Because Ubuntu does not have "runghc" in some platforms (armv7l).
* move self-made interpreters to vendor/.
* the 51st language: LOLCODE

Fixes #17.
* forgot to add lci.
* ignore a garbage file (gst.im).
* the 52nd language: Maxima
* the 53rd language: NASM
* the 54th language: Neko
* the 55th language: Nickle
* the 56th language: PARI/GP
* the 57th language: Piet
* add the dependency packages to build npiet.