No block should depend with `mustDeps` on i-jquery

`i-jquery` is just a template - so there is no reason to specify it
in `mustDeps`, jQuery code itself won't be included before the said
block in built file.

Such dependences result in `mustDeps` cycle that can not be resolved,
so, depending on a deps tech we either get an error, or some build file
that can be build correctly or not depending on a moon phase and luck
stat of the programmer.

/cc @tadatuta @arikon 
Should we add a comment describing usage of `elem` field instead of `elems` field?