ElasticSearch indexes (re-)created from slave instead of master database, if any
ElasticSearch indexes (re-)created from slave instead of master database, if any

- Added parameter "useSlave" to CM_Elastica_Type_Abstract::update()
- Ran get query of the given Elastica type on slave, whenever possible
- Used this feature in CM_Elastica_Type_Abstract::createVersioned()

Testing: Very difficult to test because CM_Db_Db caches the master/slave DB connexions, so that the DB config cannot be changed for a single test case to see where the query is being executed.

alexispeter/CM,alexispeter/CM,njam/CM,zazabe/cm,cargomedia/CM,fvovan/CM,zazabe/cm,tomaszdurka/CM,christopheschwyzer/CM,fauvel/CM,mariansollmann/CM,njam/CM,vogdb/cm,tomaszdurka/CM,mariansollmann/CM,cargomedia/CM,vogdb/cm,njam/CM,vogdb/cm,njam/CM,mariansollmann/CM,fauvel/CM,njam/CM,tomaszdurka/CM,christopheschwyzer/CM,zazabe/cm,alexispeter/CM,tomaszdurka/CM,fauvel/CM,vogdb/cm,fauvel/CM,cargomedia/CM,fvovan/CM,fvovan/CM,vogdb/cm,christopheschwyzer/CM,zazabe/cm,alexispeter/CM,christopheschwyzer/CM,fauvel/CM,fvovan/CM,tomaszdurka/CM,cargomedia/CM,mariansollmann/CM