CMake build system for Blosc

The patch includes a complete setup for building Blosc with the CMake build system.
It also provides install, uninstall, test, package and package_source targets.


Available CMake options:

* BUILD_STATIC -- ON
* BUILD_HDF5_FILTER -- OFF
* BUILD_TESTS -- ON
* BUILD_BENCHMARKS -- ON
* TEST_INCLUDE_BENCH_SINGLE -- OFF
* TEST_INCLUDE_BENCH_SUITE -- ON
* TEST_INCLUDE_BENCH_SUITE_PARALLEL -- OFF
* TEST_INCLUDE_BENCH_HARDSUITE -- OFF
* TEST_INCLUDE_BENCH_EXTREMESUITE -- OFF
* TEST_INCLUDE_BENCH_DEBUGSUITE -- OFF


Components:

* LIB: blosc.so
* DEV: static blosc.a + blosc.h
* HDF5_FILTER: blosc_filter.so
* HDF5_FILTER_DEV: blosc_filter.h

This PR supersedes FrancescAlted/blosc#17

Tested platforms:
* GNU/Linux x86_64 -- OK
* Mac OS X 10.8 (Mountain Lion) -- OK only with CC=gcc, CC=clang fails to build the dylib
* Windows -- NO not testes