Use space/tab instead of word boundary for keyword

[traytonwhite]

Potentially fixes #3 - not sure if users would want to replace other \\b instances with explicit whitespace for boundaries elsewhere in ssh-config.cson

[lalyos]

Sorry for slow response time.
@traytonwhite could you please describe me, how can i test your version?

[walles]

Adding a unit test for #3 in here would definitely help.

#6 comes with unit tests, so if / after that one is merged it shouldn't be too hard to add another test case for this.

[lalyos]

@traytonwhite or @walles if you could provide some minimal unit tests i can merge this.