App: use cont for file name
add AppData class
Util: add normalizePath
WatcherThread: use AppData
App: commit app data db
implement DocumentFile readObject
WatcherThread: don't create document if it is already exists
DocumentFile: remove useless log
PostingList: fix NullPointerException on remove
AppData: fix remove document
WatcherThread: add some useful log
Documents: fix concurrent add document
Documents: fix getNewId not continue from last id
StopWordsFilter: let user suply stop words through constructor
WatcherThread: visitStoredDocument: fix remove document
DocumentFile: remove readObject for now
fix visit stored document
Document: don't save initialized
WatcherThread: asynchronous document delete
WatcherThread: asynchronous document update