show hints on dataset matches in other DBS instances

* currently this is shown only for 1 keyword input of len>=3, e.g. andrey, zmm
* it automatically redirect to the dataset query only of keyword matche only in the current instance
  - e.g. RelValZMMGammadvmc --> dataset=*RelValZMMGammadvmc*
* otherwise, only a message/hint is shown [and only if parsing error occured], along with KWS results
  - e.g. zmm is in multiple dbs instances and can also be primary_dataset...
* TOOD: make the hints clickable (only for next release...)

fixes issue #4102

screenshots:
![andrey_multi_match](https://f.cloud.github.com/assets/213426/1887537/44c90372-79ff-11e3-832d-2f390976f240.png)
![zmm_ambigous_kws](https://f.cloud.github.com/assets/213426/1887543/64c78dc4-79ff-11e3-92d7-4e50059cd178.png)