Bugfix cache.py
	Bugfix method get_keys() of class Cache
Modifify cache.py
        Refactor dictionary used for cache entries into new class Entry
        Refactor methods update() and set_dirty() of class Cache, turning dictionary changes into explicit assignment
                This is necssary so that the dictionary storing the cache entries can be replaced by a shelve (with writeback=False property) for persistance
	Refactor methods get_size_of_dirty_data() and get_size_of_cached_data() to use _get_size_of_entry(entry)
	Add method _get_size_of_entry(entry) to class Cache, which can be overridden in subclasses
Add lru_cache.py
	Add class LinkedEntry as subclass of Entry
	Add class LRUCache as subclass of Cache, for a size limited cache
Add lru_cache_test.py
Add persistent_lru_cache.py
	Add class PersistentLRUCache as subclass of LRUCache, for persistent, less memory consuming cache with size limit
Add persistent_lru_cache_test.py
Bugfix method get_cache_expiration_time() in class CachingStore
Replace class Cache with subclass PersistentLRUCache for a persistent, size limited, and low memory cache (fix issue #2 Memory leak when copying large amount of files from Dropbox)
        Modify class CachingStore to use PersistentLRUCache
		Add parameters cache_size_in_mb and cache_id to constructor
		Modify method get_cache_expiration_time() to not access the cache data, which would influence the order of least recently used entries
        Modify method _initialize_store() of class ConfigurablePyFuseBox
                Add parameter cache_size, limiting the size of the cache in MB
                Add parameter cache_id for identifying persistent cache sessions
Modify constructor of class DataFileWrapper, to keep files smaller than 1MB in memory
Bugfix store_test.py, remove import for not yet committed error handling store wrapper
Bugfix constructor of class CachingStore, and MetaCachingStore: set default for cache_expiration_time parameter for use in store_test.py
Replace dropbox sdk v.0 with v1.5.1 - August 20, 2012, since v.0 is no longer supported (see issue #1 DropBox not authenticating)
	Modify cloudfusion/dropbox/__init__.py
	Delete cloudfusion/dropbox/auth.py
	Modify cloudfusion/dropbox/client.py
	Modify cloudfusion/dropbox/rest.py
	Add cloudfusion/dropbox/session.py
	Add cloudfusion/dropbox/six.py
	Add cloudfusion/dropbox/trusted-certs.crt
	Add cloudfusion/dropbox/util.py
Update CloudFusion to use the new Dropbox api (fix issue #1 DropBox not authenticating)
	Change class DropboxStore, to adapt to new Dropbox api
	Modify Dropbox.ini, keep backwards compatibility
		Remove unnecessary parameters
		Add new parameters cache_size, and cache_id
	Modify main.py
		Remove unnecessary import of previous Dropbox api class
Update README.rst to changes in the dropbox api