Use getCanonicalName rather than getName when emitting source, by principle.

While we only call getName() on top-level class, getCanonicalName is more
accurate when we want the source name rather than the binary name.
Remove redundant code re. finding no-args constructors.
Nit-picking, following IntelliJ IDEA suggestions.
Merge pull request #151 from tbroyer/nitpicking

Nitpicking / code cleanup