Restore "import shared" to helper_inbox

Commit 5b23d9 removed the line "import shared" from helper_inbox. Almost
all of what shared was used for became covered by helper_sql. But, shared
still needs to be imported because there is still one line that uses
shared:
9:    shared.UISignalQueue.put(('removeInboxRowByMsgid',msgid))
Show inventory lookup rate on Network Status tab
Refactor of the way PyBitmessage looks for interesting new objects in huge inv messages from peers
Merge pull request #473 from Atheros1/master

refactor inv message processing
Merge pull request #471 from Eylrid/master

Restore "import shared" to helper_inbox
Correct version number in build_osx.py
fix #474
Merge pull request #478 from Atheros1/master

fix #474
Merge pull request #477 from fanquake/build_osx-version

Correct version number in build_osx.py
modifications to API commands used by mobile device
Merge pull request #479 from Atheros1/master

modifications to API commands used by mobile device