Start supporting more specific window title detection (#75)

* Add default set of assumptions about window titles

This will leave the special cases for Google Chrome and Slack, but start getting granularity for free on windows that follow the general convention of ` - ` to separate out the application name at the end of the window title.

* Clean up name identification to make it similar for both directions

This will make it very easy to continue adding special cases for other applications

* Add support for Microsoft Edge

Go style changes

Merge pull request #45 from howeyc/nil-active

stop assuming always active window, fixes #15

osascript install instructions

Merge pull request #35 from novilabs/fix-chrome-idx-oob

do not go out of index for chrome window not having a tab open