- Added pre-commit Make target.
- Removed make test hook from pre-commit.
- Install shellcheck in TravisCI.
- Updated README.

- Added shellcheck pre-commit hook.
- Fixed issues found by shellcheck.

- Filled in fields in license.
- Removed useless checks in pre-commit.
- Added make test check to pre-commit.
- Added Travis CI.
- Updated README accordingly.

This reverts commit e4308830.

- Set default hash to sha256.
- Rename domain variable to cn to be more understood.

- Mention need to copy the CA cert to clients.

- Forgot to explicitly set the RSA key size to be 2048 (defaulted to 512).

algorithm (according to the documentation) and OpenSSL ignores the field and
uses the default, which is MD5. Setting the default hash to SHA1.