SI-6773 Changes IndexSeqFactory to be "since 2.11"

The addition of IndexSeqFactory to 2.10.x branch created a binary
incompatibility so it was removed in that branch before being released.
This commit fixes the since annotation to 2.11 on IndexSeqFactory in the
master branch.
Merge pull request #2071 from JamesIry/master_SI-6773

SI-6773 Changes IndexSeqFactory to be "since 2.11"
Objects are now consistently called objects, not modules.

The good thing is that even if we choose a different name,
this commit serves as a more or less precise documentation
of places we need to touch to fix the API.

This also solves possible confusion between Modifiers and
Modules, which used to have nearly the same identifiers in code.

Popular members in the reflection API keep the old names as
a @deprecated member.

MODULE$ and other significant binary compatibility artifacts
were left intact.
Rename items related to java.lang.Object from Object to JavaLangObject