Issue #33 - Avoid calling 'cancel()' manually

* This will prevent the infinite loop
* TODO: Any listener should call 'cancel()' safely
Issue #33 - Recompute survey languages if the languages are not set

* This fixes the problem of upgrading from an old version - 1.10.0 - of
the app.
* Create a worker thread to perform the computation.
* Store new dynamic language setting
* Add FlowApp application
Update app version to 1.12.1
Issue #40 - Read double entry flag from survey definition
Issue #40 - Add double entry functionality in FreetextQuestionView

* Capture the response if both answers match
* or if no double entry is required
Issue #40 - Warn the user on unmatched responses

* Check for double entry errors
* Disallow the user from submitting unmatched answers
Issue #40 - Warn if the first field is modified
Issue #40 - Leave unmatched texts after warning

* Only delete validation rules violations (i.e. number too long)
Issue #40 - Modify local scope variable

* readOnly flag was directly modifying the class level attribute.
Issue #40 - Move hard-coded string to resources
Issue #46 - Update Submit Tab languages
Issue #47 - Refresh home screen after bootstrap

* If the Bootstrap service installs new surveys, automatically
refresh the home screen.
Issue #49 - Delete Points of Interest features
Issue #49 - Delete helper functions/constants
Issue #49 - Delete PoI preferences
Issue #49 -Delete PoI strings
Issue #49 - Delete PoI files
Issue #50 - Hide unique identifier

* Keep filling automatically the field, but avoid displaying it.
* The data.txt serialization file keeps unchanged
Issue #48 - Allow a maximum of 500 characters

* Change the default maximum value to 500
* Always include a filter with up to 500 chars (or a specified one < 500)
Update version number