basename.go: Complete functionality

Now supports all flags and features of basename.
dirname.go: Complete functionality

Now supports all flags and features of dirname.
wc.go: A few bug fixes and an extra feature

* Forgot to call processFlags() in main
* Renamed outputPrinter to bufferProcessor
* Added a default output case
* Moved flag descriptions to const
basename.go: Don't forget to call processFlags
Merge pull request #16 from mmstick/enhancements-and-bug-fixes

Enhancements and bug fixes