Fixes #102 - Use correct assertion, avoid bad-access, and wrap lines

- ASSERT_TRUE rather than ASSERT_FALSE for default value of
  snap-to-lines
- ASSERT_EQ( 1, errorCount() ) to prevent access violation if error
  list is empty
- Use convenience function for error condition assertion
- Wrap lines to 80 columns
Merge pull request #102 from caitp/issue-102

CueSettingLine.PercentOver100 incorrectly ASSERT_FALSE(snapToLines())