Support doc comments & complex quoting

[Vindaar]

* v0.2.1
- support Nim doc comments and turn them into LaTeX comments
- support complex expressions in a quote, i.e. `x.foo.bar`.
  *Note*: *Only* dot expressions are supported. Call or command syntax
  are not allowed!
- *Potentially breaking* (unlikely): If you used the ~compile~ helper
  with ~fullBody = true~, previously it injected a ~\begin/end
  document~ around the given body. That is not really very useful, if
  one wants to pass a full TeX file to compile including header and
  everything.