merged fixes from RC_0_16

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9255 a83610d8-ad2a-0410-a6ab-fc0612d85776
fix integer overflow issue in timers

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9256 a83610d8-ad2a-0410-a6ab-fc0612d85776
add unit test for timer functions

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9257 a83610d8-ad2a-0410-a6ab-fc0612d85776
fix ambiguity invoking min

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9258 a83610d8-ad2a-0410-a6ab-fc0612d85776