Fix old method names. Add missing sample OGG file
Merge pull request #39 from silverhammermba/fix_samples

Fix old method names, missing OGG file in samples
Updated README
Fixed copy paste error with outline color
Fixed intersection bug in rect
A lot of fixes for render target
Updated readme
Updated license
Updated SFML dependency
Weird fPIC flag had been included somehow, fixed now
Remove include/lib requirements in Rakefile

If SFML is properly installed on Linux, there is no need to copy its
include and lib folders.
Make Linux build instructions simpler/agnostic

Reorder instructions to put all prerequisites (Ruby, SFML) first.
Mention `rake test` before `rake install`.

Make Ruby/SFML build instructions more agnostic. It is the user's
responsibility to figure out the best way to configure/install these
dependecies for their system. Arbitrary restrictions (e.g. "You must
compile Ruby from source") might not be true for certain systems.
Fix links for SFML source
Readd -fPIC (needed for building on (some) Linux)
Shader#bind is now Shader.bind
Texture#bind is now Texture.bind
Refactor Texture.bind
Test latest build rather than installed build

Made require paths in tests relative to rbSFML directory. This tests the
latest build rather than the latest installed build. This is good since
you can test new builds without breaking an existing one.
Merge branch 'master' into fix_tests
Use latest build for samples, run without opengl

`require` latest build rather than latest installed version. This makes
it easier to test out samples for a new build without affecting the
currently installed rbSFML.

If opengl gem isn't installed, catch the LoadError and print an error,
so `rake samples` will still run.