Corrected name in windows cross-compile

Added windows 64-bit makefile

Updated README and SDK version.

Added MinGW-based Makefile for Windows

Fixed bug with not resetting prevRMS in Energy

Added more energy features for use in speech/music discrimination.

Added peaks plugin to collection.

Removed redundant sample rate info in .n3 file which was caused errors.

Updated README to point to the new releases page.

Added last updated date for binaries.

Added link to binaries from README and .n3 file.

Added category file and modified installation instructions.

Fixed problems discovered using Vamp plugin tester.

Patch from Chris Cannam to fix initialisation and empty result errors.

Removed isysroot flags for OSX 10.6+ compatibility.