update docs for ceylon.math
fix #305
minor
oops, fix variance
add more annotations
Revert "add more annotations"

This reverts commit fb3928ac9143243ad5cf443c176305ad8902ae8b.
add less annotations 'cos I could not figure out the right incantations
to not break the model loader
Fixed minor typo in ceylon.net's `by()` in the module descriptor
Merge branch 'master' into 100-v2
[100] module dependency fixes