Changes

Implementing Precision and Scale for floating point data type
 (commit: ef3d797)

Implementing Batch Insert on PersistenceContext: introducing batchInsert(..) method.
Also modifying WriteOperation.execute(..) and WriteOperation.executeBatch(..) signature to make them return the number of affected rows.
 (commit: 8cac34e)

Implementing Batch Update on PersistenceContext: introducing batchUpdate(..) method.
 (commit: a9e0a63)

Clarify usage of placeholders in Updates, required a review of UpdateCommandBuilder logic and clarification: ColumnVariable and its subclasses are introduced to fullfill this goal.
 (commit: 04a2344)

Moving some code to an appropriate package to lighten PersistenceContext code.
 (commit: a3ea37a)

Moving Update statement criteria as a constructor parameter to clarify the API, because currently there's a mix between set(..) and where(..) methods which let one recall where(..) again and again even after set(..) has been called which is wierd.
 (commit: f3e8a3f)

Aligning Delete criteria way of doing with Update one.
 (commit: 40ed867)

Implementing Batch deletion. Still required some alignement with Update and Insert
 (commit: ecb2106)

Replacing Insert.InsertColumn by ColumnVariable to align Insert mechanism with Update and Delete ones.
 (commit: ef1a9ca)