clang-format: generate initial config

The configuration file was geneated (based on LLVM style)
by using the following command with clang-format 3.4:

    clang-format -dump-config > .clang-format
clang-format: adapt config to Monetas coding style
style: reformat code with clang-format
travis: add clang-format support
git: add pre-commit hook
Merge pull request #41 from toxeus/reformat

Reformat