enhancement, bugs fix and new features

please refer to github for v1.5.5 release issues list.
Upgrade ueditor to 1.2.6.1

fix several important editing bugs.
refer to github milestone for detailed info.
fix issues

1. several bug fix
2. change vesion number to 1.5.5
add document transition view

1. code clean up
2. i18n
3. add document transition view for download, loading, saving, error
occured issue to notify user.
bug fix on linux

1. fix gui issue on linux
2. fix build issue on linux
3. change version to 1.5.50
test
test
add xmlrpc block code
blocking sync
Bug fix

1. Fix issue author user can't edit document newly created.
2. Fix issue group attribute form not fullly occupy client area for the
first time shown.
3. Fix issue click on blank area of document list view lead crash.
4. Fix issue open encrypted document with wrong password open blank
document.
Add interface IWizSyncableDatabase
blocking sync
Add interface definition

add IWizSyncableDatabase interface to CWizDatabase, but not implemented
yet.
remove and clean

1. remove old sync thread
2. move CWizIndexBase to seperate file
3. more IWizSyncableDatabase implementation
syncing flow and interface implementation

1. optimize CWizDatabaseManager use QMap instead of QList to gain run
time efficiency and open db if not opened instead of return user
private db.
2. rewrite database path resolve method, only use single Open method
intead of openPrivate and openGroup, if user invoke Open without
kb_guid field, treat it as group database.
3. implement more IWizSyncableDatabase interface method.
change file case
Merge branch 'block-sync' of https://github.com/WizTeam/WizQTClient into block-sync
merge CWizCategoryView
download object
Add document list default badge icon