Replaced deprecated method "getEntityManager" by "getManager"

Missed part of Issue #123
Replaced deprecated getEntityNamespace by getAliasNamespace
merged branch 66Ton99/2.1 (PR #197)

This PR was submitted for the 2.1 branch but it was merged into the master branch instead (closes #197).

Discussion
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Replaced deprecated methods "getEntityNamespace" and "getEntityManager"

"getEntityNamespace" by "getAliasNamespace"
"getEntityManager" by "getManager"

Missed part of Issue #123

Commits
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7d14269 Replaced deprecated getEntityNamespace by getAliasNamespace
1aff223 Replaced deprecated method "getEntityManager" by "getManager"