Bump2version

- Document file specific options `search =` and `replace =` (introduced in 0.5.0)
- Fix parsing individual labels from `serialize =` config even if there are
characters after the last label (thanks mskrajnowski [56](https://github.com/peritus/bumpversion/pull/56)
- Fix: Don't crash in git repositories that have tags that contain hyphens [51](https://github.com/peritus/bumpversion/pull/51) and [52](https://github.com/peritus/bumpversion/pull/52)
- Fix: Log actual content of the config file, not what ConfigParser prints
after reading it.
- Fix: Support multiline values in `search =`
- also load configuration from `setup.cfg`, thanks t-8ch [57](https://github.com/peritus/bumpversion/pull/57)

This is a major one, containing two larger features, that require some changes
in the configuration format. This release is fully backwards compatible to
*v0.4.1*, however deprecates two uses that will be removed in a future version.

- New feature: `Part specific configuration`
- New feature: `File specific configuration`
- New feature: parse option can now span multiple line (allows to comment complex
regular expressions. See re.VERBOSE in the [Python documentation](https://docs.python.org/library/re.htmlre.VERBOSE) for details, also see [this testcase](https://github.com/peritus/bumpversion/blob/165e5d8bd308e9b7a1a6d17dba8aec9603f2d063/tests.pyL1202-L1211) as an example.
- New feature: `--allow-dirty` [42](https://github.com/peritus/bumpversion/pull/42)
- Fix: Save the files in binary mode to avoid mutating newlines (thanks jaraco [45](https://github.com/peritus/bumpversion/pull/45)
- License: bumpversion is now licensed under the MIT License [47](https://github.com/peritus/bumpversion/issues/47)
- Deprecate multiple files on the command line (use a `configuration file` instead, or invoke `bumpversion` multiple times)
- Deprecate 'files =' configuration (use `file specific configuration` instead)

- Add --list option [39](https://github.com/peritus/bumpversion/issues/39)
- Use temporary files for handing over commit/tag messages to git/hg [36](https://github.com/peritus/bumpversion/issues/36)
- Fix: don't encode stdout as utf-8 on py3 [40](https://github.com/peritus/bumpversion/issues/40)
- Fix: logging of content of config file was wrong

- Add --verbose option [21](https://github.com/peritus/bumpversion/issues/21) [30](https://github.com/peritus/bumpversion/issues/30)
- Allow option --serialize multiple times

- Fix: --parse/--serialize didn't work from cfg [34](https://github.com/peritus/bumpversion/issues/34)

- Don't fail if git or hg is not installed (thanks keimlink)
- "files" option is now optional [16](https://github.com/peritus/bumpversion/issues/16)
- Fix bug related to dirty work dir [28](https://github.com/peritus/bumpversion/issues/28)