chore(gradle): update build config.
chore(version): bump to 3.0.2-SNAPSHOT.
fix(stations): lock access to the list.

 Use a lock to synchronize when iterating stations or removing a station.

 Close #60.
chore(acra): update acra version.

It should fix an issue occurring only on android 2.3.

Close #68
fix: NPE when getting the connection service

Connection service may be null, relative to #71
feat: display the station number

Name will appear next to the number (%d - %s), relative to #72
feat: add preference to hide the updated at station info

Relative to #75
Minor rework around preferences and methods names
docs: update readme

Change date release format
Add next 3.1.0 release date

Relative to #74
improve: update default stations assets

Relative to #76
chore: bump to 3.1.0