Merge pull request #38 from airolson/master

Properly enclose \space in backticks
Reverse polarity of "elements" and "keys" (wrt to "sets" and "maps").
Merge pull request #45 from davidrupp/patch-1

Reverse polarity of "elements" and "keys" (wrt to "sets" and "maps").
Fix typo: replace 'the' with 'they'
Merge pull request #50 from ersiner/master

Fix typo: replace 'the' with 'they'