Use the ConvertSqlTimeColumnToEpochMs function to convert any native
datetime data type or epoch time (millisecond precision).
Refactored mysql implementation to make it more similar to postgres
and mssql implementations.
Added $__timeEpoch macro function with same implementation as $__time.
Added possibility to use a time column named time in addition to
the currectly supported time_sec.
Additional tests and update of existing.
Added test dashboard.
* $__timeFrom() -> Returns the dashboard 'from' suitable for use querying
against a MySQL TIMESTAMP field.
* $__timeTo() -> Returns the dashboard 'to' suitable for use querying
against a MySQL TIMESTAMP field.
* $__unixEpochFiler(column) -> If you store timestamps as UNIX epoch's,
this builds: column > 'from' AND column < 'to'
* $__unixEpochFrom() -> Returns the dashboard 'from' suitable for use querying
against a MySQL integer field (UNIX epochs)
* $__unixEpochTo() -> Returns the dashboard 'to' suitable for use querying
against a MySQL integer field (UNIX epochs)
