handle 'on'/'off' and 'true'/'false' correctly

[jasoncalabrese]

Hoping this resolves #1605

@oamyoamy

[coveralls]

Coverage decreased (-0.02%) to 74.565% when pulling dbe29bd on wip/off-false-etc into 4da9d51 on dev.

[codecov-io]

Current coverage is 74.58%

Merging #1626 into dev will not affect coverage as of 4da9d51

@@              dev   #1626   diff @@
=====================================
  Files          94      94       
  Stmts        8225    8225       
  Branches        0       0       
  Methods         0       0       
=====================================
  Hit          6135    6135       
  Partial         0       0       
  Missed       2090    2090       

Review entire Coverage Diff as of 4da9d51

---

Uncovered Suggestions

1. +0.28% via .../client/boluscalc.js#162...184
2. +0.25% via .../client/boluscalc.js#303...322
3. +0.22% via ...lugins/insulinage.js#73...90
4. See 7 more...

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