Adding a new Regex functionality

Define 3 new Init parameters :
regexFirstCharac, regexCoord and formatRegex

We will use it to detect coordinates in the [lon,lat] format.
If regexFirstCharac is true (in our case, '[' is found at the beginning of the line) then we display the error message in formatRegex and test for regexCoord (= are the coordinates valid decimal [lon,lat])

If regexCoord is false we keep displaying the error message, if true we carry on with the AJAX call.

------------ Extra Notes ------------
The server should detect '[' and return an empty array to the select2 ajax call. CreateSearchChoice then creates a new tag for the coordinates