Tribler crashes if the disk is full

[xoriole]

Tribler crashes if the user disk is full. Tribler should check the available disk space on startup and notify the user if the available space is insufficient.

Traceback (most recent call last):
File "/home/sandip/personal/tribler/TriblerGUI/event_request_manager.py", line 99, in on_read_data
raise RuntimeError(json_dict["event"]["text"])
RuntimeError: [Failure instance: Traceback: <class 'apsw.FullError'>: FullError: database or disk is full
/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py:1243:run
/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py:1252:mainLoop
/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py:878:runUntilCurrent
/usr/local/lib/python2.7/dist-packages/twisted/internet/task.py:239:__call__
--- <exception caught here> ---
/usr/local/lib/python2.7/dist-packages/twisted/internet/defer.py:150:maybeDeferred
/home/sandip/personal/tribler/Tribler/Core/CacheDB/SqliteCacheDBHandler.py:1285:_flush_to_database
/home/sandip/personal/tribler/Tribler/dispersy/util.py:46:helper
/home/sandip/personal/tribler/Tribler/dispersy/util.py:225:blockingCallFromThread
/home/sandip/personal/tribler/Tribler/Core/CacheDB/sqlitecachedb.py:308:executemany