fix Makefile for Mac
Merge pull request #43 from LipuFei/fix-mac-makefile

libevent loc; Makefile for Mac
compile swift with OpenSSL on Mac
fix #52: segfault while downloading many files at the same time
Merge pull request #48 from LipuFei/fix-mac-multispec

compile swift with OpenSSL on Mac.
Merged for the moment.. but need some re-work. It should be a separate config for Tribler specific builds
Merge pull request #53 from LipuFei/fix_many_downloads

check for libevent buffer
check StorageFiles if they are operational in Storage::ParseSepc()
add print_backtrace() for Windows
fix memory allocation and releasing in constructors and destructors
Merge pull request #54 from LipuFei/fix_win_path

Fix Windows path problem that causes swift segfault
make: support native clang for FreeBSD 10.0 and up

- requires gmake and libevent2 packages
-  build using `gmake swift-static` via clang