Various doc improvements (#248)
- Rename all the ugly template parameters (too long and/or starting
with an underscore).
- Rename function parameters starting with an underscore.
- Extend the doc for many classes.
- Use LaTeX-style O(...) expressions only for the complicated ones.
- A lot of small unification changes.
- Small fixes.
- Some other improvements.

 SET(PROJECT_NAME "@PACKAGE_NAME@")

 SET(PROJECT_VERSION "@PACKAGE_VERSION@" CACHE STRING "LEMON version string.")