[needs tests] Support vim-mode-plus substitute command

[mkiken]

Fixes # 128.

Changes Proposed in this Pull Request:

• Fix substitute command error in vim-mode-plus
  Error caused by searchHistory functions not existing, so I add if statements.

I have written tests for: Nothing
Sorry, I'm not sure how to test and how to write this test case...

[mkiken]

test failed :(
But in my environment(vim-mode 0.66.0, ex-mode 0.14.0), substitute/,/\n/g command to abc,def,ghi, result is

abc

def,ghi

Why?
Is my environment broken?

[jazzpi]

The tests are failing due to atom/text-buffer#224. If you are using an official version of Atom (i.e. downloaded from https://atom.io) and can confirm that bug, it might help speed up work on that.

However, the tests are currently not running on vim-mode-plus anyways, but one vim-mode. I'll hopefully get around to testing this soon™ though.

[mkiken]

@jazzpi
I usually use Atom installed by HomeBrew.Version is 1.15.0.
I try to command above using official version Atom(version 1.15.0), and confirm above bug.

I hope this helps.

[jazzpi]

I'll rewrite the specs myself, it's not actually too much effort.