Notification window to show when rebuilding cache

[dstillman]

Since we hang the UI, we kinda have to tell the user what we're doing.

[dstillman]

With faster indexing from r690, no longer a blocker for Beta 2.

Would still be good to have some sort of dedicated progress window for rebuilding the cache, since that happens before the first browser window opens on startup, but not critical (since it'll only affect the private beta testers until we actually update the fulltext logic).

[dstillman]

(In [1405]) - Added wizards for userdata schema upgrade (to give feedback during upgrades) and error reporting (to send errors to the Zotero server)

• New Actions menu option, "Report Errors...", to send chrome errors from the Error Console to the Zotero server via the error reporting wizard -- no more Advanced Instructions from the Reporting Bugs page

• Disabled unresponsive script indicator during schema upgrades, since that seems to be what caused problems during the Beta 4 upgrade

• Added repair steps for interrupted Beta 4 upgrades

• Speed up b4.r2 itemNotes repair step, which may have been what was causing the unresponsive script warning on large libraries

• Moved some Zotero.UnresponsiveScriptIndicator.enable() calls into finally{} blocks to make sure they get triggered

• New method Zotero.getSystemInfo() to get some info on the environment (platform, version, app, app version, locale) as a string for inclusion in bug reports

• Added public property skipBackup to Zotero.DB so a startup error can cancel the shutdown backup

Closes #321, Notification window to show when rebuilding cache