feature: implemented a simple optimizing JIT compiler targeting x86_64 for the Thompson VM.
merged the master branch to x64-jit.
bugfix: we did not pass the -1 fd to mmap(), which resulted in a failure at least on FreeBSD. we also print out the error message when mmap() fails.
refactor: skipped all the test cases for the Thompson JIT compiler on unsupported architectures like i386.
updated docs to reflect recent changes.
checked in benchmark tools for sregex, re1, and pcre.
use -O3 to compile sregex by default.