Remove empty std::type_info destructor.

This is provided by libcxxabi and there are actually 3 different
destructors, not just this one, so let things pick up libcxxabi correctly.
Explain what LLVM is for new users
do not warn on missing emscripten_ functions
testcase for issue #2244
fix caching of asm const strings; fixes #2253
Merge pull request #2236 from waywardmonkeys/remove-invalid-type-info-destructor

Remove empty std::type_info destructor.
Adding @dandv
Merge branch 'patch-2' of github.com:dandv/emscripten into incoming

Conflicts:
	AUTHORS
Merge branch 'patch-1' of github.com:dandv/emscripten into incoming

Conflicts:
	README.markdown
1.14.0
--emit-symbol-map option
add testcase for use of call outputs to absolute targets
improve testcase
let emcc directly access bitcode files when possible, to emit proper .d files and avoid unnecessary copies
add dependency file testing
handle --default-object-ext properly, and other emcc fixes
make tests/cases/usenullcall.ll a fastcomp-only test
eliminate X=X which can happen due to elimination
make llvm-lit test emit verbose output
testcase for i64 < 0