* add ability to set issue severity for out formats that support it based on severity rules
* fix lint issues
* change log child name
* code climate omit severity if empty
* add tests for severity rules, add support for case sensitive rules, fix lint issues, better doc comments, share processor test
* deduplicated rule logic into a base rule that can be used by multiple rule types, moved severity config to it's own parent key named severity, reduced size of NewRunner function to make it easier to read
* put validate function under base rule struct
* better validation error wording
* add Fingerprint and Description methods to Issue struct, made codeclimate reporter easier to read, checkstyle output is now pretty printed
Treat Go source files as plain text files by misspell: it allows detecting
issues in strings, variable names, etc. Also, it's the default mode of
a standalone misspell tool.
Also, implement richer and more stable auto-fix of misspell issues:
now it can fix multiple issues in one line.
