removed type hinting
changed scopes private->protected
temporary commit
fixed bug in which when the user would try to change pools in the middle of a transaction the query would be executed in the current pool instead of the new one. Pools cannot be changed in the middle of transactions so now an exception will be thrown and the changes will be rolled back.
removed internal class' constants to use global define constants. No need for duplicates.
added check for DBPOOL == null as it was affecting the pool change in the middle of transactions
fixed bug where $code was being overwritten
fixed slave lag checking bug where the error code was not properly being passed along the exception
added possibility to throw exception if we cannot check the slave lag.
placed max lag in config file (per server) and fixed samplepool config file.
changed commit and rollback to be used only on the currently working pool.
committing all changes for master merge before continuing with the functionality for users to be able to choose between read or write operations (as opposed to letting the class decide the operational mode).
Merge commit 'e8ad4f8ad66e1c87a9ad26e69cc99f4cc71726c1'