* 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
Run all linters per package. It allows unloading package data when it's
processed. It dramatically reduces memory (and CPU because of GC) usage.
Relates: #337
1. Rename in a backward compatible way
2. Remove gosec default exclude list because gosec is already disabled
by default.
3. Warn about unmatched linter names in //nolint directives
4. Process linter names in //nolint directives in upper case
5. Disable gosec for golangci-lint in .golangci.yml
1. Log all warnings, don't hide none of them
2. Write fatal messages (stop analysis) with error log level
3. Remove ugly timestamp counter from logrus output
4. Print nested module prefix in log
5. Make logger abstraction: no global logging anymore
6. Refactor config reading to config.FileReader struct to avoid passing
logger into every function
7. Replace exit codes hardcoding with constants in exitcodes package
8. Fail test if any warning was logged
9. Fix calculation of relative path if we analyze parent dir ../
10. Move Runner initialization from Executor to NewRunner func
11. Log every AST parsing error
12. Properly print used config file path in verbose mode
13. Print package files if only 1 package is analyzedin verbose mode,
print not compiling packages in verbose mode
14. Forbid usage of github.com/sirupsen/logrus by DepGuard linter
15. Add default ignore pattern to folint: "comment on exported const"
