Merge pull request #877 from chrox/opds

fix href with two slash
fix: replace showReaderUI with ReaderUI:showReader
Merge pull request #879 from houqp/houqp-master

fix: replace showReaderUI with ReaderUI:showReader
chore: cleanup FileManagerHistory:updateItemTable()
Merge pull request #880 from houqp/houqp-master

chore: cleanup FileManagerHistory:updateItemTable()
treate quoted slash as plain text in attribute value
show file size and directory items in filemanager
refresh filemanager when closing opdscatalog
add set download directory option when downloading files from OPDSCatalog
Manually added opds servers are editable and deletable by long press on
the menu entries.
add shortcut to add local calibre OPDS catalog