[wip] more and new compression algorithms

[pseyfert]

include lzo, lz4, zopfli, and brotli as compression algorithms in root. Essentially what is in pseyfert/root-compression but built into root instead of as LD_PRELOAD hack.

open issues:

• run benchmarks in this version
• extensive testing (e.g. various platforms)
• decide which parts are worth pursuing
• review license compatibilities (LZO is GPL, i.e. incompatible with root; LZ4 is BSD; ZOPFLI is APACHE; BROTLI is MIT)
• for lz4, there is also Add support for LZ4 as a compression format #81. It is worth reviewing the differences.

notable features:

• zopfli compresses in the zlib format and can thus be read even with root versions w/o zopfli