refactor database query helpers
make download file function foreceable
handle file overwrite case when a file is modified
Merge branch 'master' of github.com:cozy-labs/cozy-desktop
Merge pull request #26 from Kloadut/master

[fix] Plug two-way sync with messages to the GUI
change applyFolderDBChange

It creates missing dirs in the database instead of deleting them.
[wip] Set the sync directory to read only while applying remote changes
make applyFolderDBchanges function less wide
Merge branch 'master' of github.com:cozy-labs/cozy-desktop
Merge branch 'master' of https://github.com/cozy-labs/cozy-data-proxy
do not delete file on first sync

upload them to remote cozy instead
Merge branch 'master' of https://github.com/cozy-labs/cozy-data-proxy
[fix] Do not modify permissions for now + fetchFromDoc bugfix