qsv 0.14.0

First release of qsv (a fork of the popular xsv CSV utility) as per BurntSushi/xsv#267

It merges several PRs that been submitted since the xsv 0.13.0 release May 2018.

• rename
• fill
• transpose
• select allow regex selection
• stats added nullcount

Also implements:

• sample added the percentage option
• updated dependencies
• removed dyn deprecation warnings
• used built-in serde derive