Escape utme values `'`, `)`, and `*`

`'` => `'0`
`)` => `'1`
`*` => `'2`

Reference: [StackOverflow: Passing special values to google analytics](http://stackoverflow.com/questions/7948214/passing-special-values-to-google-analytics)
Merge pull request #7 from smerchek/escape_utme

Escape utme values `'`, `)`, and `*`
Bump version to 2.1.0 for bug fix