Updated readme with Debian instructions.

Build currently fails though, more commits incoming.
Attempt to fix a couple of build errors.
boost::filesystem::path::operator += change.

It isn't defined in Boost 1.49.0, which is what's in the Debian
repositories. Also CodeMaid decided to make an indentation change...
Added CMake settings for GCC.

GCC was building native architecture libraries. `version` library is
Windows-only too.
Include the C++0x flag in the CMakeLists.txt.
Fixed CMakeLists error.

I can't believe I never picked up on it before...
Added Travis config.

Fingers crossed this works...