Better dependency check

Dependency check now via check if "TerminalView" not in sys.modules.

UX Improvement

• added check whether TerminalView is installed
• minor improvements of README.md
• added menu entry to access key bindings
• minor code cleanup

Release 2

Expanded README.md and added name to LICENSE.

First release

First release prior to publishing to PackageControl.io.
The basic function works flawlessly with bash on Linux.