- improved `_findLineHeight` for mix-language text when line-height is not set

- improved `_findLineHeight` for mix-language text when line-height is not set
- added a new example to demonstrate the slightly-improved `_findLineHeight`
- fixed file path in example pages so that they work when repos was cloned to custom directory other than `FTColumnflow'.


Before:
![Before](https://f.cloud.github.com/assets/138707/242709/4ffb9ad4-8a27-11e2-8c1a-570776ae1ee6.png)

After:
![After](https://f.cloud.github.com/assets/138707/242710/5b7bfa66-8a27-11e2-8a85-7d4ae6af655f.png)