Updated copyright-header in source files to year 2014.

Also added missing headers in new source files.
Unified include-guards.

Most guards used VIENNAGRID_XXX_FILENAME_HPP, but some used the pattern
VIENNAGRID_XXX_FILENAME_GUARD. This commit unifies this to use only
the former.
Updated version number to 2.1.0.
Updated license header for examples and tests to reflect year 2014.
Unified text in README.md with the project description on GitHub.
README: Removed text on ViennaData requirement (leftover)
LICENSE: Updated current year.