Factor out allocMemory_orDIe(...) in simple_compressionCCtx.c, and amend Makefile to account for dependency on utils.h

travis: Use script instead of Cmd env

btultra2

and fixed nit

[regression] add more methods

as requested in #1391

Advanced API

notably while using multi-threading

as suggested by @terrelln

to introduce btultra2

get information on which config is currently tested
so that console get animated during long tests.

restored ability to copy/paste the resulting compression level table into zstd_compress.c .

Refactor examples to avoid code duplication.

and ensure zstdbench detects out-of-bound parameters

introducing ZSTD_btultra2

Add buck build instructions to README.md

also : fixed paramgrill, and limit conditions