v2.1.0

Changes since v2.0.2:

• colwriter: panic on cmd execution
• Travis: check vendor
• add hack/tree_status.sh to check the tree status
• README: spell checks, minor rewording
• fix regression of vgrep -s $SELECTORS
• update integration-test
• fix interactive regression
• fix regression for empty input
• interactive: print help on empty input
• append additional args to show command
• make output/logs consistent
• embed cli args into vgrep type
• move state into a vgrep type
• remove Log variable in favor logrus API
• Fix some spelling mistakes in comments
• Add missing return for 'show' command
• Avoid race conditions when reading/writing cache file
• Makefile: refactor container build targets
• move ansi & colwriter to ./internal
• update vendored libraries
• Makefile: add vendor target
• bump Travis to go 1.11.x
• don't error out if cache file doesn't exist
• fix travis
• add integration tests
• README: remove notes about 2.0.0 release
• logging: use string instead of *os.File
• Update vendor/
• README: add Travis CI build status
• add Travis CI