Remove redundant #include <cstdint> in several places
dispatcher: __builtin_cpu_supports is only available on x86

This is a critical bug that breaks build on ARM with GCC
cmake: Build the documentation only after the library is tested
Several fixes in QtCreator project files
Release 0.9.3

Commit 0cadc5cac3a2b0e2553b01c6f58cc8054294417e fixes a critical bug.
no particular need for postfix return type
compare.h doesn't need postfix return types either
unused variables in memory_{load,store}.h
Merge branch 'uncontroversial' of https://github.com/mtklein/libsimdpp into uncontroversial