Add script_number to VS builds.
msvc min/max constexpr no use "LEAST", comment on msvc sign warning
Incorrect secp256k1 linkage for one msvc build.
Add/fix ec_keys, script and scriptnum tests in msvc build.
Temp fix up for lack of dynamic build of secp256k1 library.
Integrate BOOST_TEST_DYN_LINK into MSVC builds and remove comment.
Merge pull request #10 from evoskuil/develop

Fix msvc projects for recent changes.